MEDICAL    SCHOOL 


COLLEGE   OF  PHARMACY 


CALIFORNIA   COLLEGE 
of  PHARMACY 


EXPERIMENTAL  PHYSIOLOGY 
AND  ANATOMY 


BY 

WALTER   HOLLIS   EDDY,   A.M.,  PH.D. 
^ 

HEAD   OF  THE   DEPARTMENT   OF   BIOLOGY  IN  THE   HIGH   SCHOOL   OF 

COMMERCE,    NEW    YORK    CITY,    AND    ASSOCIATE    IN 

THE    DEPARTMENT    OF    BIOCHEMISTRY 

COLUMBIA   UNIVERSITY 


Qallfcrnla  CoHe^a  of  Pharmacy 


REVISED   EDITION 


NEW  YORK      •  I  •      CINCINNATI      • :  •      CHICAGO 

AMERICAN    BOOK    COMPANY 

* 


COPYRIGHT,  1906,  1911,  BY 
WALTER  HOLLIS  EDDY 


Eddy's  Experimental  Physiology 
w.  P.    4 


PREFACE 


THOUGH  the  importance  of  Physiology  in  secondary  schools 
is  everywhere  recognized,  little  attempt  has  been  made  to 
place  the  subject  on  an  experimental  basis.  The  recent 
great  advances  in  physiological  chemistry  have  directed  the 
attention  to  the  possibilities  of  the  experimental  method  as 
a  means  of  investigating  the  principles  of  the  subject.  This 
book  represents  a  selection  of  experimental  matter  which 
is  adapted  to  the  age  of  elementary  students  of  the  subject 
and  which,  at  the  same  time,  will  present  the  facts  of  physi- 
ology in  a  concrete  form. 

The  starred  topics  in  the  following  table  of  contents  con- 
stitute a  brief  course  covering  that  which  is  most  essential; 
and  the  optional  exercises  make  it  possible  to  extend  the  work 
at  the  discretion  of  the  teacher.1  The  ingenuity  of  the 
teacher  will  readily  suggest  substitutes  for  the  material 
suggested  when  the  laboratory  facilities  of  the  school  are 
inadequate. 

Some  of  the  exercises  may  be  made  demonstrations,  and 
time  in  school  may  be  saved  by  assigning  some  of  the  simpler 
exercises  as  part  of  the  home  work  of  the  pupil. 

In  the  present  edition  several  changes  have  been  made, 
based  partly  on  experience  gained  in  teaching  the  first  edition 
and  partly  on  the  advance  in  scientific  knowledge  of  the 

1  The  book  in  its  starred  topics  meets  the  requirements  of  the  New 
York  State  Syllabus,  and  as  a  whole  has  been  accepted  by  the  Harvard 
College  authorities  as  meeting  the  entrance  requirements  of  that  Insti- 
tution. 


4  PREFACE 

subject.  It  has  been  found,  for  example,  that  certain  phases 
of  elementary  chemistry  need  emphasis  for  proper  appreci- 
ation of  later  phases  of  pure  physiology.  To  that  end,  exer- 
cises on  chemical  and  physical  change,  and  on  mixtures  and 
solutions  have  been  introduced.  Again,  new  reagents  have 
been  devised  to  facilitate  various  tests;  for  example,  the  Bene- 
dict solution  in  place  of  the  less  stable  Fehling's  solution,  and 
the  biuret  reagent,  which  does  away  with  the  complicated  pro- 
cedure for  the  biuret  test  for  protein.  The  collodion  bag 
dialyzer  is  another  laboratory  device  which  has  simplified  the 
teaching  of  osmosis  and  has  accelerated  the  process  so  that 
with  it  osmotic  pressures  may  be  obtained  in  twenty  minutes 
that  formerly  required  some  hours.  The  wording  of  many 
experiments  has  been  altered  and  the  procedure  shortened 
and  simplified  to  enable  the  principle  to  be  more  readily 
grasped.  For  example,  in  the  digestion  experiments  the 
work  has  been  rearranged  in  such  a  way  as  to  separate 
the  determination  of  the  conditions  for  digestion  from  the 
mere  process  of  digestion  and  thus  permit  the  pupil  to 
reach  the  conclusions  separately  and  with  added  emphasis 
and  clarity.  The  recent  changes  in  our  views  as  to  the  nature 
of  fat  digestion  and  the  action  of  bile  are  also  developed  in 
new  forms  of  experiment,  and  this  change  typifies  another 
form  of  improvement  in  the  present  edition. 

I  wish  to  acknowledge  again  the  many  helpful  suggestions 
given  me  by  my  colleagues  of  the  High  School  of  Commerce 
and  by  others  in  various  parts  of  the  country  who  have 
called  my  attention  to  faults  in  the  earlier  edition.  To  Dr.  E. 
A.  Darling  of  Harvard  College  and  to  Mr.  Frank  0.  Payne  of 
the  High  School  of  Commerce  I  am  especially  indebted  for 
their  aid  and  critical  review  of  the  manuscript  of  the  first 
edition.  Many  of  the  improvements  in  methods  and  labora- 
tory devices  I  owe  directly  to  my  association  with  and  to 


PREFACE  5 

suggestions  from  Professor  William  J.  Gies  of  the  Columbia 
University  Department  of  Biological  Chemistry,  notably  the 
collodion  bag  dialyzer  and  the  biuret  reagent.  To  Dr.  Stanley 
R.  Benedict  I  beg  to  give  credit  for  the  solution  which 
bears  his  name.  To  Mr.  C.  W.  Harm,  my  colleague  in  the 
High  School  of  Commerce,  I  am  also  indebted  for  valuable 
suggestions  based  upon  teaching  experiments  with  the  first 
edition.  Finally,  I  wish  to  acknowledge  my  debt  to  my  wife 
for  assistance  in  many  details  of  grammatical  arrangement 
and  mechanical  labor  involved  in  the  work. 

WALTER  H.  EDDY. 

THE  HIGH  SCHOOL  OF  COMMERCE, 
NEW  YORK. 


METHOD    OF   EXPEKIMENT 


IT  has  been  my  purpose  so  to  state  each  of  the  following 
exercises  as  to  admit  of  its  performance  by  the  pupil  with 
a  minimum  amount  of  direction  from  the  teacher.  Most 
of  the  exercises  should  be  thus  performed  by  each  pupil 
individually,  or  by  two  pupils  together;  but  of  course  the 
teacher  may  select  as  many  as  desired  for  performance  as 
demonstrations  before  the  class. 

It  is  essential  that  each  pupil  make  a  suitable  record  of 
all  exercises  performed,  in  a  carefully  prepared  notebook. 
It  is  recommended  that  a  separate-leaf  notebook  be  used 
for  this  purpose,  as  this  makes  possible  the  inspection  of 
one  set  of  exercises  without  handling  the  entire  books,  and 
permits  the  rewriting  of  unsatisfactory  work  without  dis- 
turbing the  arrangement  of  the  book. 

It  is  generally  agreed,  too,  that  the  book  should  consist 
of  original  reports  made  at  the  time  of  experiment,  and  not 
of  matter  copied  from  original  rough  drafts. 

Frequent  examination  of  all  laboratory  notes  by  the 
teacher  is  also  essential  to  good  work,  and  the  proper  status 
of  the  notebook  work  can  be  secured  only  by  giving  it  a 
definite  proportion  in  the  marking  of  the  pupil's  work. 
A  rubber  stamp  with  the  word  " Approved"  and  the  in- 
structor's name  may  be  obtained  of  any  stationer  at  small 
expense  and  wi1!  greatly  facilitate  the  work  of  correction. 
Neatness  as  well  as  accuracy  and  adequacy  of  report  should 
receive  proper  weight  in  the  marking  of  notebook  work. 

7 


8  METHOD    OF    EXPERIMENT 

When  the  work  is  completed  the  student  should  prepare 
an  index  of  drawings,  records  of  experiments,  and  descrip- 
tions of  demonstrations  contained  in  the  notebook.  It  is 
well  to  indicate  in  this  index,  after  each  title,  whether  the 
work  was  done  by  the  pupil  or  observed  and  recorded  by 
him,  and  whether  in  the  laboratory  or  as  home  work. 

The  following  directions  may  prove  of  value  as  indicating 
a  satisfactory  method  of  arrangement  of  a  notebook  record: 

A.  Record  the  number  and  date  of  the  exercise. 

B.  Make  drawings  of  the  apparatus  used,  when  neces- 

sary, and  label  them  properly. 

C.  State  as  briefly  as  possible: 

(1)  What  was  done. 

(2)  What  happened  as  the  result  of  (1). 

(3)  What  meaning  these  results  have,  and  the 

purpose  of  the  exercise. 

D.  Answer  all  questions  in  the  text  and  try  to  con- 

dense your  statements  into  as  concise  and  brief 
a  form  as  possible. 

The  exercises  as  a  rule  should  precede  the  text  study  and 
serve  as  a  basis  for  such  study. 


TABLE    OF   CONTENTS 


Required  topics  are  indicated  by  a  star  (*) ;  the  others  are  optional. 
PRELIMINARY  EXERCISES 

BXERCISB  PAGE 

I.   GLASS  BENDING  AND  CUTTING 13 

II.  COLLECTION  OF  GASES 14 

INTRODUCTORY  EXERCISES  IN  PHYSICS  AND  CHEMISTRY 

III.  CHEMICAL  CHANGE 16 

IV.  PHYSICAL  CHANGE 16 

V.   MIXTURES  AND  SOLUTIONS 17 

*VI.  PROPERTIES  OF  PHOSPHORUS 18 

*VII.   PROPERTIES  OF  SULPHUR 18 

*VIII.   PROPERTIES  OF  CARBON 19 

*IX.   PROPERTIES  OF  IRON 21 

*X.  OXYGEN  AND  OXIDATION 21 

*XI.  PROPERTIES  OF  OXYGEN 23 

*XII.   COMPOSITION  OF  AIR  AND  PROPERTIES  OF  NITROGEN..  25 

XIII.  COMPOSITION  OF  WATER 26 

XIV.  PROPERTIES  OF  HYDROGEN 28 

*XV.  ACIDS,  BASES,  SALTS,  AND  NEUTRALIZATION 29 

STUDY  OF  NUTRIENTS 

*XVL   PROTEINS 31 

*XVII.  CARBOHYDRATES  —  STARCH 33 

*XVIII.  CARBOHYDRATES  —  GRAPE  SUGAR  (GLUCOSE)  AND  CANE 

SUGAR  (SUCROSE) 33 

*XIX.  FATS  AND  OILS 34 

XX.   MINERAL  SALTS 35 

XXI.  WATER 36 

STUDY  OF  FOODS 

*XXII.   NECESSITY  OF  FOOD 37 

*XXIII.   NUTRIENTS  PRESENT  IN  COMMON  FOODS 38 

*XXIV.   STUDY  OF  FOOD  CHARTS 39 

9 


10 


TABLE    OF    CONTENTS 


HlSTOLOGICAL   STUDIES 


EXERCISE  PAGE 

*XXV.   PARTS  OF  A  CELL 41 

*XXVI.   STUDY  OF  A  PLANT  CELL 42 

*XXVII.   STUDY  OF  LIVING  PROTOPLASM  —  AMCEBA 43 

XXVIII.  EPITHELIAL  TISSUE 47 

XXIX.   CONNECTIVE  TISSUE 48 

XXX.    MUSCULAR  TISSUE 50 

XXXI.  NERVOUS  TISSUE 51 

PRINCIPLES  OF  DIGESTION 

*XXXII.  PRINCIPLES  OF  OSMOSIS 52 

*XXXIII.  AN  ENZYME 54 

*XXXIV.  A  FERMENT  ORGANISM  —  YEAST 56 

*XXXV.  STRUCTURE  OF  A  TYPICAL  GLAND 57 

ORGANS  AND  PROCESSES  OF  DIGESTION 

*XXXVI.   DISSECTION  OF  RAT'S  DIGESTIVE  ORGANS 58 

*XXXVII.   THE  TEETH 60 

XXXVIII.   PREPARATION  OF  DIGESTIVE  FLUIDS 62 

*XXXIX.   SALIVARY  DIGESTION 63 

*XL.   PEPTIC  DIGESTION 66 

*XLI.   PANCREATIC  DIGESTION 68 

*XLIL   STUDY  OF  DIGESTIVE  ACTION  OF  BILE 69 

XLIII.   MICROSCOPIC  ANATOMY  OF  THE  DIGESTIVE  TRACT.  . .  70 

XLIV.  TABULATION  OF  NUTRIENT  DIGESTION 71 

BLOOD 

*XLV.   GENERAL  PROPERTIES  OF  BLOOD 72 

*XLVI.   STUDY  OF  Ox  OR  HOG  BLOOD 74 

XLVII.   CRYSTALLIZATION  OF  HAEMOGLOBIN  FROM  BLOOD 76 

XLVIII.   DETECTION  OF  BLOOD  IN  BLOOD  STAINS 76 

CIRCULATION  AND  THE  BLOOD  SYSTEM 

*XLIX.   PROPERTIES  AND  LOCATION  OF  ARTERIES  AND  VEINS  . .  78 

*L.   CIRCULATION  IN  A  FROG'S  FOOT 79 

LI.   MINUTE  STRUCTURE  OF  ARTERIES  AND  VEINS 80 

*LII.   STRUCTURE  OF  THE  HEART 81 


COLLEGE 

TABLE  OF   CONTENDS 


11 


THE  BODY  SKELETON 

EXERCISE  PAGE 

*LIII.   STUDY  OF  THE  SKELETON 86 

*LIV.   GROSS  STRUCTURE  OF  BONES 86 

LV.   COMPOSITION  OF  BONE 88 

*LVI.   STRUCTURE  OF  A  JOINT 88 

*LVII.   FORMS  OF  JOINTS 89 

MUSCLES  AND  MOTION 

*LVIII.   DISSECTION  OF  THE  MUSCLES 90 

*LIX.   GROSS  STRUCTURE  OF  MUSCLE 91 

LX.   NERVE  MUSCLE  PREPARATION 91 

LXI.   STUDY  OF  LEVER  ACTION 93 

LXII.   LEVERS  OF  THE  BODY 94 

RESPIRATION 

*LXIII.   DISSECTION  OF  A  RAT'S  LUNGS 96 

*LXIV.   MECHANICS  OF  RESPIRATION 97 

*LXV.   STUDY  OF  EXPIRED  AIR 98 

EXCRETION 

LXVI.  STUDY  OF  A  LAMB'S  KIDNEY 99 

*LXVII.  STUDY  OF  THE  SKIN 100 

NERVOUS  SYSTEM 

*LXVIII.   DISSECTION  OF  SHEEP'S  BRAIN 103 

*LXIX.   DISSECTION  OF  SPINAL  CORD 107 

SPECIAL  SENSES 

*LXX.   NERVE  ACTION 109 

*LXXI.   CUTANEOUS  SENSATIONS 109 

*LXXII.    STUDY  OF  THE  TONGUE 110 

*LXXIII.   SENSATIONS  OF  TASTE  AND  SMELL 110 

LXXIV.   HEARING;  LAWS  OF  SOUND Ill 

*LXXV.   VISION;  DISSECTION  OF  SHEEP'S  EYE 112 

*LXXVI.  ACTION  OF  THE  EYE 114 

BACTERIA 

"LXXVIL  STUDY  OF  BACTERIA.  .  117 


EXPEEIMENTAL    PHYSIOLOGY 
AND  ANATOMY 


PRELIMINARY  EXERCISES 


I.  —  GLASS  BENDING  AND  CUTTING  (OPTIONAL) 

Apparatus.  —  Several  pieces  of  quarter-inch,  glass  tubing  about  two 
feet  in  length,  a  three-cornered  file,  a  Bunsen  burner  with  fishtail 
attachment. 

Directions.  —  A.  Bending.  Place  the  fishtail  attach- 
ment on  the  burner  and  light  the  gas.  Hold  at  the  ends 
the  tube  which  is  to  be  bent  and  bring  into  the  flame  the 


Fio.   1. 

part  at  which  you  wish  the  bend  (see  Fig.  1).  Turn  the 
tube  constantly  to  insure  equal  heating  of  all  parts,  and 
when  the  glass  is  flexible  remove  from  the  flame  and  bend 
the  two  ends  slowly  toward  each  other  until  the  desired 
angle  is  obtained.  Use  care  to  keep  the  two  ends  in  the 
same  plane,  and  do  not  bend  quickly,  as  that  would  cause 

13 


la  PRELIMINARY   EXERCISES 

buckling.     If  the  glass  cools  too  soon  return  it  to  the  flame 
and  treat  as  before. 

B.  Cutting.  Wet  the  file  and,  holding  the  tube  firmly 
with  finger  and  thumb,  make  a  slight  scratch  across  it. 
Turn  the  tube  over  and  repeat  the  operation  at  a  point 
directly  opposite.  Now  grasp  the  tube  in  both  hands,  one 
on  each  side  of  the  scratches,  and  bend  sharply.  The  result 
should  be  a  clean,  square-ended  break.  The  edges  may  be 
rounded  by  holding  them  in  the  flame  a  moment. 


II.  —  COLLECTION  OF  GASES  (OPTIONAL) 

Apparatus.  —  Pneumatic  trough  and  support,  glass  tube  bent  at 
right  angles,  large-mouthed  bottles,  piece  of  glass  to  cover  mouth  of 
bottle. 


Directions.  —  A.   Fill  the  trough  with  water  to  the  depth 

of  a  half  inch  above  the 
top  of  the  support.  Fill 
the  bottle  with  water, 
cover  the  mouth  with 
the  glass,  and  invert, 
putting  the  mouth  under 
the  water  of  the  trough. 
Remove  the  piece  of 
glass,  and  place  the  bot- 
tle over  one  of  the  holes 
of  the  support.  Does 
the  water  flow  out?  Ex- 
plain. 

Now    introduce    the 


FIG.  2. 


short    end    of    the    glass 
tube  into  the  mouth  of  the  bottle  (see  Fig.  2)  and  blow 


PRELIMINARY   EXERCISES  15 

through  the  other  end.  Where  does  this  gas  go?  Why? 
Would  this  method  of  collecting  gases  be  successful  if  they 
were  readily  soluble  in  water? 

B.  Fill  a  second  bottle  with  water  and  invert  in  the  same 
way  as  the  first.     Bring  the  one  containing  the  gas  under 


FIG.  8. 


the  one  containing  the  water,  and  gradually  turn  it  mouth 
upward  (see  Fig.  3).  In  this  way  gases  may  be  transferred 
from  one  vessel  to  another  for  study. 


INTRODUCTORY  EXERCISES  IN   PHYSICS 
AND   CHEMISTRY 


III.  —  CHEMICAL  CHANGE  (OPTIONAL) 

Apparatus.  —  Powdered  sulphur,  test  tube,  strip  of  copper  foil, 
Bunsen  burner. 

Directions.  —  Examine  the  sulphur  and  copper  foil  care- 
fully and  write  a  description  of  each,  stating  the  character- 
istic features  of  each  substance. 

Next,  place  a  strip  of  copper  foil  an  inch  long  in  the  test 
tube  and  cover  to  the  depth  of  a  quarter  inch  with  powdered 
sulphur.  Heat  the  tube  in  the  flame  of  the  lamp  and  note 
every  change  that  takes  place.  State  the  changes  that 
take  place  in  the  sulphur  in  the  order  of  their  occurrence. 
State  what  happens  to  the  copper.  When  no  further  change 
occurs,  remove  the  strip  from  the  tube  and  examine  it  care- 
fully. Does  it  bend  easily?  Is  it  the  color  of  copper? 
Can  you  find  any  sulphur?  Is  the  strip  copper?  Sulphur? 
Give  reasons  for  your  statement.  Changes  that  result  in  a 
new  substance  with  new  properties  are  called  chemical 
changes.  Write  a  statement  giving  your  opinion  as  to 
whether  this  was  a  chemical  change  and  include  in  this 
statement  your  reasons  for  your  conclusion. 

IV.  —  PHYSICAL  CHANGE  (OPTIONAL) 

Apparatus.  —  Ice,  chemical  thermometer,  beaker,  tripod,  Bunsen 
burner. 

Directions.  —  Place  several  pieces  of  ice  in  the  beaker 
and  stir  it  about  with  the  thermometer.  Note  the  tempera- 

16 


PHYSICS    AND    CHEMISTRY  17 

ture  of  the  ice.  Next,  light  the  burner  and  heat  the  ice 
gently.  What  happens  to  the  ice?  Does  the  temperature 
rise?  Was  this  change  in  the  ice  like  that  of  the  sulphur  or 
copper?  Reason  for  your  answer. 

Continue  the  heating  until  the  temperature  rises  no 
further.  What  is  the  reading  at  this  point?  What  change 
is  taking  place?  Is  it  a  chemical  change?  Reasons  for 
answer. 

Write  a  statement  comparing  the  changes  observed  in 
Exercises  III  and  IV  and  explain  the  differences  between 
them. 

V.  —  MIXTURES  AND  SOLUTIONS  (OPTIONAL) 

Apparatus.  —  Powdered  chalk,  table  salt,  water,  4  beakers,  2  fun- 
nels, filter  paper,  2  evaporating  dishes,  2  Bunsen  burners. 

Directions.  —  A.  Fill  a  beaker  half  full  of  water  and 
stir  into  it  a  teaspoonful  of  powdered  chalk.  What  appear- 
ance has  the  water?  Fit  a  filter  paper  into  a  funnel  and  pour 
half  of  the  chalk  and  water  mixture  through  the  filter  into 
the  second  beaker.  Compare  the  filtered  and  unfiltered 
portions.  Pour  half  the  filtered  portion  into  an  evaporating 
dish  and  evaporate  to  dryness.  Is  any  residue  left  in  the 
dish? 

B.  Repeat  the  steps  given  in  A  with  the  rest  of    the 
apparatus,  but  substitute  a  teaspoonful  of  salt  for  the  chalk. 
Record  the  results  as  in  A. 

C.  Compare  the  results  of  A  and  B  and  from  your  com- 
parison answer  these  questions:     (a)  Does   chalk  dissolve 
in  water?     (6)  Does  salt?     (c)  How  can  you  demonstrate 
the  solubility  or  insolubility  of  any  substance? 


18  EXPERIMENTAL   PHYSIOLOGY 

X    VI.  —  PROPERTIES  OF  PHOSPHORUS 

Apparatus.  —  Piece  of  yellow  phosphorus,  evaporating  dish,  forceps, 
knife. 

Directions.  —  (Caution!  Phosphorus  should  be  kept  un- 
der water  and  cut  under  water.  It  should  not  be  allowed 
to  come  in  contact  with  the  bare  skin.) 

Fill  the  evaporating  dish  with  water  and  with  the  forceps 
place  the  piece  of  phosphorus  in  it.  With  the  knife  cut  off 
a  piece  and  examine  the  cut  surface.  Does  it  cut  easily? 
What  color  is  the  new  cut  surface?  Leave  this  exposed  to 
the  light  for  a  time,  keeping  it  under  water,  and  note  any 
change  in  color.  Is  phosphorus  soluble  in  water?  1u- 

Pick  up  a  piece  with  the  forceps,  wipe  dry  with  filter  or 
blotting  paper,  and  hold  in  the  air  a  moment.  Describe 
what  takes  place.  Why  is  phosphorus  kept  under  water? 
Does  phosphorus  give  off  any  odor? 

Rub  phosphorus  gently  ori  a  piece  of  paper  and  examine 
the  paper  afterwards  in  the  dark.  What  evidence  have  you 
that  phosphorus  burns  at  a  low  temperature? 

(Bone  and  brain  are  the  parts  of  the  body  richest  in  phos- 
phorus.) 

Make  a  list  of  the  properties  of  phosphorus  so  far  as  you 
have  observed  them. 

VII.  —  PROPERTIES  OF  SULPHUR 

Apparatus.  —  Half  a  teaspoonful  of  flowers  of  sulphur  or  a  piece 
of  stick  sulphur,  a  silver  spoon,  a  hard-boiled  egg,  a  raw  egg,  an 
evaporating  dish,  alcohol  lamp  or  Bunsen  burner. 

Directions.  —  Examine  a  little  of  the  sulphur.  Describe 
its  odor,  taste,  color.  Shake  some  up  in  water.  Does  it 
dissolve? 


*ARMACY 

PHYSICS   AND    CHEMISTRY  19 

Place  a  little  in  the  dry  evaporating  dish  and  heat  gently. 
Does  it  melt?  Describe  its  condition*.  Continue  to  heat, 
and  describe  the  various  changes  through  which  it  passes.. 

Touch  a  match  to  a  little  dry  sulphur.  Does  it  burn? 
Describe  the  result.  Smell  of  the. fumes  (Caution!).  Where 
have  you  noticed  this  odor  before?  (This  odor  is  due  to 
a  gas  called  sulphur  dioxide  and  this  gas  is  formed  whenever 
sulphur  is  burned.) 

Place  a  little  of  the  sulphur  in  the  bowl  of  the  silver 
spoon.  After  a  moment  brush  it  off.  Is  the  silver  still 
bright?  (When  silver  is  brought  in  contact  with  sulphur 
the  latter  unites  with  it  and  forms  a  compound  called  silver 
sulphide,  which  is  black.) 

Mince  the  hard-boiled  egg  with  the  handle  of  the  silver 
spoon.  What  happens?  Compare  with  above  result.  Eggs 
contain  sulphur. 

Place  the  raw  egg  in  a  clean  evaporating  dish  and  leave 
in  a  warm  place  for  several  days.1  When  the  egg  decays 
note  the  odor.  (This  odor  is  due  to  another  compound  of 
sulphur  called  hydrogen  sulphide.  When  animal  flesh  decays 
it  gives  off  this  odor,  showing  that  flesh  contains  sulphur.) 

Mention  seven  properties  of  sulphur  which  you  have  ob- 
served in  the  above  experiments. 

/ 
VIII.  —  PROPERTIES  OF  CARBON 

Apparatus.  —  Stick  of  wood  charcoal,  bottle  with  a  small  mouth, 
limewater,2  glass  tube  six  or  eight  inches  long,  beaker,  test  tubes, 
splinter  of  wood,  pieces  of  meat,  piece  of  marble,  hydrochloric  acid. 

1  It  is  Well  to  place  the  dish  in  a  closed  vessel  containing  a  little  water,  as 
otherwise  the  egg  may  dry  up  without  decaying. 

2  Limewater  may  be  made  by  shaking  a  little  quicklime  in  water,  allow- 
ing the  mixture  to  settle  and  decanting  the  clear  liquid. 


20  EXPERIMENTAL   PHYSIOLOGY 

Directions.  —  Examine  the  charcoal  stick.  (Charcoal  is 
one  of  the  forms  of  carbon.)  Describe  its  color,  odor,  taste. 
Does  it  dissolve  in  water? 

Light  the  stick,  after  trimming  it  to  such  a  size  as  to  enable 
it  to  be  thrust  through  the  neck  of  the  bottle.  Does  it  give 
off  any  odor  in  burning?  Is  it  like  or  unlike  sulphur  in  this 
respect? 

Thrust  the  lighted  stick  of  charcoal  into  the  bottle  and 
keep  it  there  until  the  flame  goes  out.  Now  remove  it  and 
cover  the  mouth  of  the  bottle  with  the  finger.  Can  you  see 
anything  in  the  bottle?  Pour  a  little  clear  lime  water  into 
the  bottle  and  shake  the  bottle.  What  happens  to  the  color 
of  the  lime  water?  What  sort  of  substance  must  be  present 
in  the  bottler  (When  carbon  burns  it  forms  a  gaseous 
compound  with  the  oxygen  of  the  air  called  carbon  dioxide. 
This  gas  is  the  only  one  that  will  cause  the  change  in  lime- 
water  noted  above.) 

Rinse  out  the  bottle  with  water.  Light  the  wood  splinter 
and  thrust  into  the  bottle.  Proceed  as  with  the  charcoal. 
Test  the  contents  of  the  bottle  with  limewater.  What 
evidence  have  you  that  wood  contains  carbon? 

Burn  the  piece  of  meat  by  heating  it  in  the  test  tube. 
Pour  limewater  into  the  tube.  What  evidence  have  you 
that  animal  flesh  contains  carbon? 

Place  the  piece  of  marble  in  a  clean  test  tube.  Pour  on  it 
a  little  hydrochloric  acid  which  has  been  diluted  previously 
with  twice  its  volume  of  water.  What  evidence  of  action  have 
you?  Suspend  a  drop  of  limewater  in  the  mouth  of  the  tube. 
Hydrochloric  acid  and  water  contain  no  carbon;  what  must 
you  conclude  as  to  the  presence  of  carbon  in  the  marble? 

(Carbon  is  to  be  found  in  all  animal  and  vegetable  com- 
pounds and  in  some  minerals.) 


PHYSICS   AND    CHEMISTRY  21 

Pour  some  of  the  limewater  into  the  beaker.  By  means 
of  the  glass  tube  blow  some  of  your  breath  through  the 
liquid  in  the  beaker.  In  what  form  is  the  carbon  in  your 
breath?  (Expired  air  contains  about  4  parts  of  this  gas  in 
every  100  parts  of  the  expired  air.  Ordinary  air  contains 
about  .04  part  of  this  gas  in  100  parts,  or  about  4  parts  in 
every  10,000  parts  of  air.) 

(Besides  charcoal,  the  other  forms  of  carbon  are  diamond 
and  graphite.  All  the  forms  of  carbon  are  odorless,  taste- 
less, and  insoluble  in  water;  and  if  strongly  heated  in  the 
presence  of  oxygen,  each  form  of  carbon  will  combine  with 
it  and  form  carbon  dioxide.) 

IX.  —  PROPERTIES  OF  IRON 

Apparatus.  —  Several  feet  of  fine  wrought-iron  wire,  a  magnet,  an 
evaporating  dish. 

Directions.  —  Bring  the  magnet  in  contact  with  the  iron. 
Raise  the  magnet.  Note  the  result.  See  if  other  things 
act  similarly  toward  the  magnet. 

Place  a  coil  of  the  wire  in  a  warm,  dry  place.  Place  a  like 
coil  in  the  evaporating  dish  and  cover  with  water.  Leave 
both  coils  for  several  days,  and  then  examine  them.  Note 
any  differences  between  the  two  coils.  What  conditions  are 
favorable  to  this  change?  (Rust  is  a  compound  that  iron 
forms  with  the  oxygen  of  air  and  water.  It  is  this  power 
of  iron  to  unite  with  oxygen  that  makes  it  valuable  as  a 
part  of  the  blood  in  the  animal  body;  see  Exercise  XL VI, 
last  paragraph.) 

'  X.  —  OXYGEN  AND  OXIDATION 

Apparatus. — Red  oxide  of  mercury  (mercuric  oxide),  test  tube, 
stick  of  charcoal,  limewater  and  glass  tube,  Bunsen  burner. 

Directions.  —  Place  in  a  test  tube  as  much  red  oxide  as 
you  can  get  on  your  finger  nail.  Heat  the  test  tube  in  the 


22  EXPERIMENTAL   PHYSIOLOGY 

flame  (see  Fig.  4.)1  Heat  the  end  of  the  charcoal  stick  until 
it  glows,  and  introduce  it  into  the  mouth  of  the  test  tube. 
After  heating  the  oxide  hot  you  will  notice 
a  change  in  the  glow  of  the  charcoal.  De- 
scribe it.  Can  you  see  anything  in  the 
tube?  If  it  be  a  colorless  gas  that  is  act- 
ing on  the  charcoal  can  that  gas  be  air? 
Reasons  for  your  statement. 

Remove  the  tube  from  the  flame.     When 
the  stick   ceases  to   glow  remove   it  and 
substitute  for  it  a  drop  of  limewater  on  the 
end  of  the  glass  tube.     What  happens?     What  does  this  in- 
dicate?    As  the  tube  cools  what  do  you  see  on  the  sides  of 
the  tube?     Do  you  know  the  name  of  this  substance? 

EXPLANATION.  Oxide  of  mercury  is  a  compound  of  mer- 
cury (quicksilver)  and  oxygen.  Heat  decomposes  this  into 
oxygen  and  mercury.  In  what  form  were  these  two  sub- 
stances given  off  in  the  above  experiment?  We  have  al- 
ready learned  that  when  charcoal  burns  it  forms%  a  gas  called 
carbon  dioxide.  How  was  this  gas  formed  in  the  above  exer- 
cise? We  can  express  the  above  actions  in  the  form  of 
equations  as  follows: 

(1)  Oxide  of  mercury  =  oxygen  and  mercury. 

(2)  Oxygen  +  carbon  =  oxide  of  carbon. 

In  chemical  language  the  process  illustrated  in  (1)  is 
analysis,  or  the  separation  of  a  compound  into  its  parts. 
The  process  illustrated  in  (2)  is  synthesis,  or  the  union  of 
parts  to  make  a  compound.  All  chemical  actions  may  be 
grouped  under  one  or  the  other  of  these  processes. 

The  special  kind  of  compound  that  results  from  the  union 

1  The  flame  of  an  alcohol  lamp  is  not  hot  enough  to  produce  the  changes 
described  in  this  experiment. 


PHYSICS   AND    CHEMISTRY  23 

of  oxygen  with  a  substance  is  called  a  compound  of  oxida- 
tion, and  the  actual  formation  is  called  oxidation.  When 
oxidation  takes  place  rapidly,  light  and  heat  are  produced 
at  the  same  time  and  the  process  is  called  rapid  oxidation 
or  combustion.  Give  examples  from  your  experience  of  both 
kinds  of  oxidation  —  the  slow  and  the  rapid.  Why  does  the 
exclusion  of  air  from  a  fire  cause  the  fire  to  go  out?  What 
is  the  precise  action  of  water  or  sand  when  thrown  on  a 
flame,  in  the  light  of  the  above  explanation?  Write  a  full 
statement  of  what  took  place  in  the  above  experiment. 

XI.  —  PROPERTIES  OF  OXYGEN 

Apparatus.  — Chlorate  of  potash  (potassium  chlorate),  manganese 
dioxide,  piece  of  phosphorus,  stick  of  charcoal,  sulphur,  fine  iron  wire, 
Florence  flask,  one-holed  rubber  stopper,  rubber  and  glass  connect- 
ing tubing,  wash  bottle  fitted  with  two-holed  stopper,  ring  stand, 
sand  bath,  pneumatic  trough,  five  large-mouthed  glass  bottles  with 
glass  plates  to  cover,  caustic  soda,  Bunsen  burner  or  alcohol  lamp, 
deflagrating  spoon. 

Directions.  —  Set  up  the  apparatus  as  in  Fig.  5.  Place 
in  the  flask  to  a  depth  of  half  an  inch  a  mixture  of  one  part 
of  manganese  dioxide  to  four  parts  of  chlorate  of  potash. 
Fill  the  wash  bottle  about  half  full  of  water  and  dissolve 
a  stick  of  caustic  soda  in  it.1  When  everything  is  connected 
as  in  the  diagram  heat  the  flask  gently  on  the  sand  bath. 
The  first  of  the  gas  produced  will  mix  with  the  air  in 
the  apparatus  and  should  be  allowed  to  escape.  When  the 
bubbles  of  gas  flow  freely  through  the  delivery  tube,  fill 
one  of  the  bottles  with  water  and  invert  over  the  delivery 
tube  to  receive  the  gas  (oxygen)  as  in  the  above  diagram 
(see  Exercise  II  on  page  14).  When  the  bottle  is  full  cover 
with  the  glass  plate  and  set  aside,  mouth  upward.  Fill 
1  This  will  absorb  the  impurities  in  the  oxygen. 


24 


EXPERIMENTAL   PHYSIOLOGY 


the  other  four  bottles  in  the  same  way.     Then  proceed  as 
follows: 

A.  Examine  the  gas  in  the  first  bottle.     Describe  its  color 
and  odor.     Suck  a  little  into  the  mouth  with  a  glass  tube. 
Has  it  any  taste? 

B.  Tie  a  piece  of  charcoal  to  the  handle  of  the  deflagrat- 
ing spoon,  heat  the  end  of  the  charcoal  until  it  glows,  and 


FIG.  5. 

introduce  it  into  the  second  bottle.  Describe  the  result. 
Keep  lowering  the  charcoal  as  it  tends  to  stop  burning,  until 
it  reaches  the  bottom  of  the  bottle.  Compare  this  result 
with  that  of  Ex.  X.  What  name  do  you  give  to  this  process? 
How  could  you  test  the  contents  of  the  bottle  to  prove  your 
statement?  Do  so  and  record  result  (see  Ex.  VIII). 

C.  Place  in  the  bowl  of  the  deflagrating  spoon  a  piece 
of  phosphorus  the  size  of  a  pea  (Caution!  Handle  with 
forceps  and  cut  under  water.)  Light  the  phosphorus  and 
introduce  quickly  into  the  third  bottle.  Describe  the  result. 


PHYSICS  AND   CHEMISTRY  25 

Does  it  burn  more  or  less  brilliantly  than  in  air?  Note  the 
white  cloud  in  the  bottle.  (This  is  an  oxide  of  phosphorus 
and  is  formed  by  the  uniting  of  the  phosphorus  and  the 
oxygen.)  Compare  this  result  with  that  in  B. 

D.  After  cleaning  the  deflagrating  spoon  place  some  pow- 
dered sulphur  in  it.     Light  the  sulphur.     Note  how  it  burns 
in  air  and  the  color  of  the  flame.     Now  introduce  it 

into  the  fourth  bottle.  Describe  the  result.  After  the 
burning  is  over  smell  (Caution!)  the  gas  in  the  bottle. 
Compare  with  the  odor  of  burning  sulphur  in  Ex.  VII. 
What  is  the  name  of  this  gas?  Is  the  action  noted 
above  combustion?  Give  your  reasons.  (See  Ex.  X.) 

E.  Heat  the  end  of  the  fine  iron  wire  red  hot  and 
introduce  it  into  the  fifth  bottle.     Describe  the  result. 
After  the  action  is  over  examine,  the  red  spots  on  the 
sides  of  the  bottle  and  compare  them  with  the  rust 
obtained  in  Ex.  IX.     What  is  the  difference  between  FIG.  6. 
the  two  actions? 

Name  the  properties  of  oxygen  that  you  have  observed. 

XII.  —  COMPOSITION  OF  AIR  AND  PROPERTIES  OF 
NITROGEN 

Apparatus.  —  Pneumatic  trough,  bell  jar  closed  at  the  top,  evap- 
orating dish,  test  tube,  phosphorus. 

Directions.  —  Fill  the  pneumatic  trough  so  as  just  to  cover 
the  support.  Place  the  evaporating  dish  on  the  support. 
Place  in  it  a  piece  of  phosphorus  the  size  of  a  pea;  light  the 
phosphorus,  and  cover  quickly  with  the  bell  jar. 

A.  Note  the  white  fumes  that  appear.  What  are  these? 
(See  Ex.  XI,  C.)  What  is  one  of  the  components  of  air? 
When  the  jar  is  first  put  on,  note  that  some  bubbles  are  forced 
out  because  the  heat  causes  the  air  to  expand  a  little.  The 


26 


EXPERIMENTAL   PHYSIOLOGY 


FIG.  7. 


phosphorus  stops  burning  when  all  the  oxygen  in  the  bell 

jar  is  used  up.  Let  the  apparatus 
stand  until  the  white  oxide  of  phos- 
phorus has  been  absorbed  by  the 
water  and  the  gas  in  the  jar  is  clear. 
(Phosphorus  was  used  instead  of 
sulphur  or  charcoal  in  this  exer- 
cise because  its  oxide  is  a  solid 
which  settles  and  dissolves  in  the 
water.)  Has  the  water  risen  in 
the  jar?  What  part,  by  volume, 
of  the  jar  does  it  occupy?  Since 
the  phosphorus  has  used  up  all  the  oxygen  in  burning,  about 
what  part  of  air  must  be  oxygen? 

B.  Fill  the  test  tube  with  gas  from  the  bell  jar  in  the 
manner  described  in  Ex.  II,  B.  Examine  this  gas.  De- 
scribe its  color,  odor,  taste.  Place  a  lighted  match  in  it. 
What  happens?  Explain.  (This  gas  is  called  nitrogen.1) 
Of  what  advantage  is  the  presence  of  nitrogen  in  the  air? 
Why  is  a  good  draft  necessary  to  make  a  fire  burn  freely? 
If  the  body  needs  to  take  in  oxygen  constantly  why  can  we 
not  live  in  a  sealed  room?  Compare  the  properties  of 
nitrogen,  air,  and  oxygen. 

XIII.  —  COMPOSITION  OF  WATER  (OPTIONAL) 

Apparatus.  —  Electrolysis  apparatus,2  sulphuric  acid,  four  dry 
cells,  splinters  of  wood,  test  tubes,  pneumatic  trough  or  other  dish 
of  water,  glass  and  rubber  connecting  tubing. 

1  Other  gases  (carbon  dioxide,  argon,  water  vapor)  are  present  in  very 
small  proportions. 

2  For  the  electrolysis  apparatus  shown  on  p.  27  may  be  substituted 
simpler  forms  with  nearly  as  good  results.     Simple  forms  are  shown  in 
Clark  and  Dennis's  "  Elementary  Chemistry,"  page  33,  and  in  Remsen's 
"  Chemistry,  Briefer  Course." 


PHYSICS  AND   CHEMISTRY 


27 


Directions.  —  Open  the  two  stopcocks  and  fill  the  ap- 
paratus with  water  containing  5  per  cent  of  sulphuric  acid. 
When  the  tubes  are  full  and  all  air  is 
driven  out,  close  the  cocks;  arrange  the 
four  dry  cells  in  series  (positive  pole  of 
one  connected  with  negative  pole  of  the 
next,  and  so  on),  and  connect  the  pos- 
itive and  negative  poles  of  the  series 
with  the  posts  as  indicated  in  Fig.  8. 
Note  what  happens.  Where  do  the 
bubbles  form?  In  which  tube  do  they 
form  most  rapidly?  What  is  the  ratio 
by  volume  of  the  gases  in  the  two  tubes? 
When  the  tube  containing  the  most 
gas  is  full,  disconnect  the  cells.  Collect 
in  a  test  tube  the  gas  from  the  tube  con- 
taining the  lesser  amount  as  follows: 
With  rubber  tubing  connect  an  ordinary 
delivery  tube,  filled  with  water,  to  the  top  of  the  gas  tube. 
Insert  the  end  of  the  delivery  tube  into  the  mouth  of  the 

test  tube,  after  filling  the 
test  tube  with  water  and 
inverting,  as  in  Ex.  II. 
Open  the  cock  and  col- 
lect the  gas,  as  in  Fig.  9. 
Cover  the  mouth  of  the 
tube  with  the  thumb  and 
hold  it  mouth  upward. 
FlG-  9*  Now  remove  the  thumb 

and  quickly  insert  a  lighted  splinter  into  this  collected  gas. 
What  happens?  What  gas  have  you  studied  that  produces 
a  similar  action?  This  is  the  same  gas. 


FIG.   8. 


28 


EXPERIMENTAL   PHYSIOLOGY 


In  a  second  test  tube  collect  the  gas  in  the  other  tube. 
Hold  it  mouth  downward,  and  introduce  a  lighted  splinter 
into  it.  Describe  what  happens.  How  is  this  gas  different 
from  oxygen?  from  nitrogen?  (The  name  of  this  new  gas 
is  hydrogen.  The  electric  current  has  dissociated  the  com- 
pound —  water  —  into  two  parts  hydrogen  and  oxygen.) 
Is  this  exercise  synthesis  or  analysis? 

XIV.  —  PROPERTIES  OF  HYDROGEN  (OPTIONAL) 

Apparatus.  —  Granulated  zinc  or  pieces  of  sheet  zinc,  dilute  sul- 
phuric acid,1  bottle  with  two-holed  stopper,  thistle  tube,  glass  and 
rubber  connecting  tubing,  pneumatic  trough,  large-mouthed  bottle, 
test  tubes. 

Directions.  —  Set  up  the  apparatus  as  in  the  diagram. 
Place  a  handful  of  zinc  in  the  bottle  and  pour  on  enough 

dilute  sulphuric  acid  through 
the  thistle  tube  to  cover  the 
zinc.  (Caution!  Keep  all 
flames  away  from  the  appa- 
ratus until  the  gas  is  col- 
lected.) Let  this  gas  escape 
until  it  is  bubbling  freely 
from  the  delivery  tube;  then 
collect  the  large  bottle  full, 
through  water,  as  in  Ex.  XI.2 
A.  By  the  method  of  Ex. 
II,  B,  take  some  of  the  gas  in  a  test  tube  and  examine  it, 
holding  the  test  tube  mouth  downward.  Describe  its  color, 
odor,  taste. 

1  To  dilute  sulphuric  acid,  pour  slowly  one  part  of  concentrated  acid 
into  five  or  six  parts  of  water.     Stir  while  pouring. 

2  The  gas  will  be  freer  of  impurities  if  passed  through  a  wash  bottle 
containing  permanganate  solution. 


FIG.    10. 


PHYSICS   AND    CHEMISTRY  29 

B.  Collect  a  second  test  tube  full  and  hold  mouth  down- 
ward as  before.     Tie  a  match  to  a  wire,  light  the  match,  and 
thrust  it  up  into  the  tube.     Does  the  match  continue  to 
burn?     Reason?     Where  does  the  hydrogen  burn?     Why? 
After  the  hydrogen  has  burned  up,  examine  the  sides  of 
the  tube.     What  do  you  find  on  them?     Why  should  you 
expect  this?     What  is  oxide  of  hydrogen? 

C.  Hold  a  fresh  tube  full  of  hydrogen  mouth  upward 
for  a  few  moments.     At  the  end  of  that  time  test  with  a 
match.     Is   the   hydrogen   still   there?     Explain.     (Hydro- 
gen is  the  lightest  substance  known.)     Make  a  list  of  the 
properties  of  hydrogen. 

XV.  —  ACIDS,  BASES,  SALTS,  AND  NEUTRALIZATION. 

Apparatus.  —  Dilute  hydrochloric  and  nitric  acids  (one  part  acid 
to  ten  parts  water),  caustic  soda,  red  and  blue  litmus  paper,  evapo- 
rating dish,  glass  stirring  rod,  Bunsen  burner. 

Directions.  —  A.  Examine  some  of  the  dilute  hydrochloric 
acid.  What  sort  of  odor  has  it?  Describe  its  taste.  Rub 
some  between  the  fingers;  describe  its  "  feel."  Dip  a  piece 
of  red  litmus  into  it.  What  is  the  effect?  Dip  in  a  piece 
of  blue  litmus.  Describe  the  result.  (The  taste,  "  feel/' 
and  effect  on  litmus  noted  are  three  ways  in  which  to 
detect  an  acid.)  Test  some  common  substances  with  red 
and  with  blue  litmus  and  record  results;  e.g.,  cream  of 
tartar,  vinegar,  soda,  fruit  juices,  ammonia. 

B.  Dissolve  a  stick  of  caustic  soda,  an  inch  long,  in  a 
tumbler  of  water.  Examine  this  liquid.  What  is  its  taste? 
odor?  "  feel  "?  Te&t  it  with  the  two  kinds  of  litmus  paper 
and  record  results.  (This  kind  of  substance  is  called  a  base. 
Bases  always  react  in  this  way  to  taste,  ('  feel/'  and  litmus. 


30  EXPERIMENTAL   PHYSIOLOGY 

Certain  strong  bases  are  called  alkalis.)     Test  the  substances 
named  in  A.     Which  of  these  are  bases? 

C.  Pour  some  of  the  caustic  soda  solution  into  the  evap- 
orating dish.     Add,  gradually,  the  dilute  hydrochloric  acid, 
stirring  with  the  rod  and  testing  with  the  litmus  until  the 
solution  turns  neither  red  litmus  blue  nor  blue  litmus  red. 
If  too  much  acid  is  added  correct  it  with  more  basic  solu- 
tion.    The  acid  and  the  base  are  now  said  to  be  neutralized, 
and   the  process    is   called  neutralization.     Evaporate  this 
mixture  to  dryness  over  the  flame.     What  sort  of  substance 
is  left  in  the  dish?     Taste  it.     Is  it  familiar?     Does  it  affect 
litmus  in  the  solid  state  or  when  dissolved  in  water? 

D.  Repeat  the  above  neutralization,  using  nitric  acid  in- 
stead of  hydrochloric.     Does  the  product  affect  litmus? 

(The  products  of  C  and  D  are  called  neutral  salts.  To  this 
class  of  substances  belong  most  of  the  minerals  of  the  earth.) 
This  exercise  may  be  continued  with  other  acids  and  bases 
at  the  desire  of  the  experimenter. 


STUDY  OF  NUTRIENTS 


Phosphorus,  sulphur,  carbon,  iron,  oxygen,  nitrogen,  and 
hydrogen  are  a  few  of  the  chemical  elements  to  be  found  in 
plant  and  animal  bodies.  These  elements  occur,  however, 
not  as  elements,  but  in  combinations,  or  compounds.  There 
are  many  of  these  combinations,  but  they  may  be  grouped 
together  under  a  few  class  names.  These  classes  of  com- 
pounds show  certain  definite  qualities  by  means  of  which 
their  presence  may  be  detected.  The  classes  are  called  proxi- 
mate principles,  or  nutrients.  The  most  important  are: 

Proteins,  or  nitrogenous  compounds.1 

Carbohydrates,  or  starches  and  sugars. 

Fats  and  oils. 

Mineral  salts. 

Water. 

XVI.  —  PROTEINS 

Apparatus.  —  Raw  white  of  egg,  olive  oil,  salt,  nitric  acid,  ammonia, 
Millon's  reagent,2  Biuret  reagent,3  test  tubes. 

Directions.  —  A .  Put  a  little  raw  white  of  egg  (a  good 
example  of  protein)  in  a  test  tube,  cover  with  two  inches 
of  water,  and  shake.  Does  the  white  of  egg  dissolve? 
Shake  the  mixture  and  note  the  result.  Heat  the  water 

1  The  American  Biochemical  Association  has  revised  its  nomenclature 
and  agreed  upon  the  use  of  the  word  protein  to  designate  this  class  of 
compounds,  restricting  the  word  proteid  to  a  definite  group  under  the 
general  class  of  proteins. 

2  To  make  Millon's  reagent,  mix  one  part  of  mercury  by  weight  with 
two  parts  of  nitric  acid  (concentrated  commercial) :  when  the  mercury  is  all 
dissolved,  dilute  with  twice  the  volume  of  water. 

3  To  make  biuret  reagent,  make  first  1000  c.c.  of  20  per  cent  solu- 
tion of  caustic  soda  in  water.     Then  to  this  add  (a  few  drops  at  a  time 
with  constant  stirring)  10  c.c.  of  3  per  cent  copper-sulphate  solution. 

31 


32  EXPERIMENTAL    PHYSIOLOGY 

and  egg  mixture  slowly.  What  form  does  the  white  of  egg 
take  now?^-5g^bhis  form  soluble  in  water?  ^x^> 

Put  a  second  portion  of  the  egg  in  a  test  tube.  Add 
dilute  nitric,  acid  to  it.  What  happens  to  the  white  of 
egg?  '  Compare  the  action  with  that  in  boiling  water.  &«-~ 

(This  action  of  acid  and  heat  on  a  protein  like  egg  albu- 
min is  called  coagulation.)  Why  does  a  piece  of  meat  (which 
is  composed  mainly  of  a  protein  like  white  of  egg)  become 
more  solid  under  heat?  *z*^-*^&+~£ 

B.  Xanthoproteic  Test.     Place  a  little  coagulated  white  of 
egg  in  a  test  tube  and  cover  with  dilute  nitric  acid.     Heat 
to  boiling,  and  then  add  enough  .ammonia  to  neutralize  the 
acid  and  give  an  alkaline  test.     The  white  of  egg  (protein) 
takes  what  color?     Treat  in  the  same  way  some  olive  oil, 
some  common  salt,  and  any  other  substance  that  does  not 
contain  protein.     Do  any  of  these  take  the  same  color  as 
the  white  of  egg? 

C.  Millon's  Test.     Add  enough  Millon's  reagent  to  a  little 
coagulated  white  of  egg  to  cover,  and  raise  the  temperature 
gradually  by  holding  the  test  tube  several  inches  above  the 
flame.     What  color  does  the  egg  and  the  solution  become? 
Treat  the  other  substances  mentioned  in  B  in  the  same 
way.     Do  they  act  like  the  egg? 

D.  Biuret  Test,  or  Piotrowski's  Reaction.     To  a  little  white 
of  egg  in  water  add  10  c.c.  of  biuret  reagent.     Note  the  color 
change."  Boil  the  mixture.     Does  the  color  change?      Note 
the  result.     Test  the  other  substances  mentioned  in  B  in 
the  same  way.      ^V<^.^M^ 

(Of  the  three  chemical  tests  for  protein  given  above,  the 
xanthoproteic  is  best  for  general  use.  There  are  many 
forms  of  protein,  but  these  tests  will  indicate  its  presence 
whatever  its  form  may  be.) 


STUDY   OF   NUTRIENTS  33 

XVII.  —  CARBOHYDRATES  —  STARCH 

Apparatus.  —  Solution  of  iodine, l  laundry  starch,  white  of  egg, 
olive  oil,  test  tubes. 

Directions.  —  Place  a  little  starch  in  a  test  tube  and  fill 
the  tube  a  quarter  full  of  water.     Shake  it.     Does  the  starch 
dissolve? "  Prove  your  statement  by  applying  one  of  the  tests        /,- 
described  in  Exercise  V.     Boil.    What  happens  to  the  starch?  J 

Put  a  little  of  the  starch  paste  in  a  test  tube  with  an 
inch  of  water.  (Shake,  to  get  thorough  mixture.)  Now  add 
a  drpp  pf  the  solution  of  iodine.  What  co^or  does  the  paste  be- 
come?^ Heat.  What  becomes  of  the  color?  ^Should  the  iodine 
test  be  applied  to  hot  or  cold  starch-containing  substances?  <£*<-J? 

Test  a  little  white  of  egg  and  olive  oil  (which  contain  no 
starch)  in  the  same  way.  Do  you  get  the  same  result?  ^  ». 

(This  test  will  indicate  the  presence  of  starch,  whatever 
may  be  its  form.) 

XVIII. —  CARBOHYDRATES  —  GRAPE  SUGAR  (GLUCOSE) 
AND  CANE  SUGAR  (SUCROSE) 

Apparatus.  —  Fehling's  solution2  or  Benedict's  solution,3  glucose, 
starch,  oil,  test  tubes,  concentrated  hydrochloric  acid,  cane  sugar. 

1  To  make  the  iodine  solution,  dissolve  a  teaspoonf ul  of  potassium  iodide 
crystals  in  a  tumbler  of  water.  Add  crystals  of  iodine  and  stir  until  a  rich 
wine  color  is  obtained.  This  may  be  bottled  and  used  as  needed. 

2  To  make  Fehling's  solution: 

Fehling's  solution  is  composed  of  two  definite  solutions  —  a  cupric 
sulphate  solution  and  an  alkaline  tartrate  solution. 

Cupric  sulphate  solution  =  34.65  grams  cupric  sulphate  dissolved 
in  500  c.c.  of  water. 

Alkaline  tartrate  solution  =  125  grams  potassium  hydroxide  or  sodium 
hydroxide  and  173  grams  of  Rochelle  salts  dissolved  in  500  c.c.  of  water. 
Keep  these  solutions  separate  until  ready  for  use.  Prepare  for  test  by 
mixing  equal  portions. 

3  Dr.  S.  R.  Benedict  has  devised  a  substitute  for  Fehling's  solution 


34  EXPERIMENTAL  PHYSIOLOGY 

Directions.  —  A.  Dissolve  a  little  of  the  glucose  in  water 
in  a  test  tube.  Add  5  c.c.  of  Benedict's  solution  (or  Fehling's 
solution)  and  heat  to  boiling.  Note  any  changes  in  color. 
When  no  further  change  in  color  takes  place,  note  the  final 
color.  Let  the  solution  stand  and  note  that  the  colored  part 
separates  out  as  a  precipitate.  Test  in  the  same  way  oil, 
starch  and  any  other  substance  that  contains  no  grape 
sugar.  Compare  results. 

(This  is  a  universal  test  for  grape  sugar.) 

B.  Test  for  Cane  Sugar  (Sucrose).  To  5  c.c.  of  a  weak 
solution  of  cane  sugar  add  an  equal  volume  of  concentrated 
hydrochloric  acid.  Boil.  A  deep_red  color  indicates  cane 
sugar.  4-v — 

XIX.  —  FATS  AND  OILS 

Apparatus.  —  Flaxseed  (ground),  beef  fat,  unglazed  paper,  ether, 
filter  paper,  glass  funnel,  evaporating  dish,  chemical  thermometer. 

Directions.  —  A.  Put  a  little  beef  fat  in  the  evaporating 
dish  and  heat.  When  it  begins  to  melt  stir  with  the  chemi- 
cal thermometer  and  note  the  temperature  of  the  melting 
point.  If  the  body  temperature  is  98°  F.  what  does  this 
experiment  indicate  as  to  the  condition  of  fats  in  the  body? 
Name  some  fats  that  are  liquid  at  ordinary  temperatures. 

which  has  the  advantage  of  not  deteriorating  on  long  standing.     It  is 
prepared  as  follows: 

"  With  the  aid  of  heat  dissolve  173  grams  of  sodium  citrate  and  100 
grams  of  sodium  carbonate  in  about  600  c.c.  of  water.  Pour  through 
filter  paper  into  a  glass  graduate  and  make  up  to  850  c.c.  with  water. 
Dissolve  17.3  grams  of  cupric  sulphate  in  100  c.c.  of  water  and  make  up 
to  150  c.c.  with  more  water.  Pour  the  carbonate-citrate  solution  into  a 
large  beaker  and  add  the  cupric-sulphate  solution  slowly,  with  constant 
stirring.  The  mixed  solution  is  ready  for  use  and  does  not  deteriorate 
on  long  standing." — Hawk's  "Practical  Physiological  Chemistry,"  1910. 


STUDY  OF  NUTRIENTS  35 

B.  Place  a  little  beef   fat  on  the  unglazed  paper  and 
warm.     Remove   and    examine    the    paper.     How    does    it 
show  the  presence  of  fat?    ^Substitute  for  the  beef  fat  a 
little  ground  flaxseed  and  repeat  the  above  process.     Does 
flaxseed  act  like  beef  fat?  ^t)o  starch  and  other  substances 
which  contain  no  fat  or  oil  act  in  the  same  way?     (The 
above  is  a  general  test  for  fats  and  oils  in  whatever  form 
they  may  be.) 

C.  Burn  a  little  fat  and  note  the  odor.      This  odor  is 
characteristic  of  fats. 

D.  Place  a  little  beef  fat  in  a  test  tube.     Add  enough 
ether  to  cover,  and  shake.     Describe  the  effect  on  the  fat. 
Filter  off  the  ether,  by  means  of  the  funnel  and  filter  paper, 
into  the  evaporating  dish.     Let  the  latter  stand  until  the 
ether  evaporates.     What  is  left  in  the  dish?     What  did  the 
ether  do  to  the  fat?     Treat  ground  flaxseed  in  the  same 
way.     Is  the  result  the  same?     Treat  sugar,  or  anything 
else  that  contains  no  fat  or  oil,  in  the  same  way.     Is  the 
result  the  same?      (The  above  method  enables  us  to  extract 
fat  from  a  substance  which  contains  it.) 

XX.  —  MINERAL  SALTS  (OPTIONAL) 

Apparatus.  —  Platinum  foil  or  piece  of  sheet  iron,  forceps,  piece 
of  meat  or  vegetable  matter. 

Directions.  —  Place  the  meat  on  the  foil  and  hold  the 
foil  in  the  flame  with  the  forceps  until  all  the  black  has 
disappeared  from  the  burning  meat.  The  residue  is  min- 
eral matter.  Would  this  test  be  possible  if  this  mineral 
matter  were  combustible?  What  color  is  the  residue? 
(This  is  the  method  for  determining  the  presence  and 
amount  of  mineral  salts.) 


36  EXPERIMENTAL   PHYSIOLOGY 

XXI.  —  WATER  (OPTIONAL) 

Apparatus.  —  Pieces  of  parsnip,  potato,  apple,  lettuce  leaves,  flour, 
meal,  meat,  test  tube,  balance  sensitive  to  one  gram. 

Directions.  —  A.  Heat  one  of  the  above  substances  in  a 
dry  test  tube.  As  the  tube  cools  after  having  been  taken 
from  the  flame,  examine  the  sides  and  note  what  you  see 
on  them. 

B.  Weigh  a  portion  of  each  of  the  above  substances,  re- 
cord the  weights,  and  place  the  substances  in  a  warm,  dry 
place  for  a  few  days.  Then  weigh  again  and  record  as  be- 
fore. Continue  this  until  there  is  no  further  decrease  in 
weight.  The  loss  of  weight  represents  approximately  the 
water  contained  in  the  substances  before  it  evaporated. 
From  your  results  answer  the  following  questions:  About 
what  per  cent  of  water  did  each  substance  contain?  Why 
are  flour  and  grains  in  general  a  good  food  for  travelers  to 
carry?  Why  are  fruits  and  salads  good  hot-weather  foods? 


"*'  COLLEGE 
PHARMACY 


STUDY  OF  FOODS 


XXII. 


NECESSITY  OF  FOOD 

Apparatus.  —  Wide-mouthed  bottles,  corks  to  fit,  pea  or  corn  seed- 
lings, nutrient  solution,1  test  tubes,  paraffin  wax,  distilled  water. 

Directions  —  A.  Take  one  of  the  pea  or  corn  seedlings 
and  cut  off  the  cotyledons  close  to  the 
stem.  Pass  this  through  a  hole  in  one 
of  the  corks,  and  insert  in  a  bottle,  as 
shown  in  Fig.  11.  Fill  the  bottle  about 
three-quarters  full  of  the  nutrient  so- 
lution. Prepare  a  second  seedling  in  the 
same  way  (select  one  of  as  nearly  the 
same  size  as  possible),  but  substitute 
distilled  water  for  the  nutrient  solution. 
Note  the  growth  of  each  seedling  for  sev- 
eral days.  Do  they  grow  equally  fast? 
What  sort  of  food  is  in  the  nutrient 
solution?  From  the  composition  of  the 
water  and  the  mineral  salts,  is  it  pos- 
sible for  the  plant  to  get  its  carbon  from  the  nutrient  solu- 

1  Nutrient  Solution  after  Sachs  ('82) : 

Distilled  water  (H20) 1000. 00 


FIG.  11. 


Potassium  nitrate  (KNOs) 

Sodium  chloride  (NaCl) 

Calcium  sulphate  (CaSO4) 

Magnesium  sulphate  (MgSO4) 

Calcium  phosphate  (CaslPO 4L)   

Ferric  chloride  (FeCl3) 


1.00 
0.50 
0.50 
0.50 
0.50 
0.005 


c.c. 

gram 


(Do  not  put  the  ferric  chloride  into  the  solution  in  the  first  place,  but 
add  a  drop  of  it  to  each  bottle  when  the  seedlings  are  put  in.) 

37 


38 


EXPEKIMENTAL,   PHYSIOLOGY 


tion?  (Air  contains  a  small  proportion  of  carbon  dioxide 
[see  Ex.  XII]  and  plants  secure  their  carbon  through  their 
leaves,  which  absorb  the  gas  from  the  air.)  From  your  obser- 
vations can  a  plant  live  indefinitely  on  water  alone? 

B.  Seal  the  growing  seedling  of  A  to  the  cork  with  melted 
paraffin  wax,  cover  the  upper  part  of  the  seedling  with  a 
test  tube,  and  seal  the  edges  of  the  tube  to  the  cork.     Does 
the  plant  continue  to   live?     (Plants  cannot   live  without 
air.)     What  collects  on  the  inside  of  the  tube?     What  evi- 
dence have  you  that  a  plant  gives  off  water? 

C.  Prepare  a  third  and  a  fourth  seedling  as  in  A.     In  one 
bottle  put  some  nutrient  solution  made  without  the  potas- 
sium nitrate,  and  in  the  other  the  normal  solution.     Which 
seedling  lives  longest?     (To  support  life,  one  food  required 
by  plants  is  some  nitrogen  salt  like  potassium  nitrate.) 

D.  Prepare  a  fifth  seedling  as  in  A,  using  a  nutrient  so- 
lution with  only  the  ferric  chloride  omitted.     After  several 
weeks,  notice  the  effect  on  the  color  of  the  plant. 

XXIII.  —  NUTRIENTS  PRESENT  IN  COMMON  FOODS 

Apparatus.  —  Meat,  flour,  milk,  parsnip,  lettuce,  peanuts,  and  the 
necessary  materials  for  the  tests  described  in  Exs.  XIII  to  XVIII. 

Directions.  —  Apply  the  tests  to  each  substance  separately 
and  tabulate  your  results  as  follows: 
Substance  Tested.  —  .  $ 


NAME  OF  TEST 

REAGENT  USED 

COLOR  OR 
OTHER  RESULT 

NUTRIENT  INDICATED 

<*  H"Hv  >  r»  vrfr*  IC, 

...  ,.,••-. 

/r 

:- 

o 

K.^,v-  - 

STUDY   OF   FOODS 


39 


Under  "  Reagent  "  tell  the  chemicals  used. 

Under  "  Color  or  Other  Result "  state  exactly  what 
happens. 

Under  "  Nutrient  Indicated  "  write  the  name  of  nutrient 
and  the  word  present  or  absent. 

XXIV.  —  STUDY  OF  FOOD  CHARTS  1 


FOOD 

COMPOSITION  PERCKNTAGB  OF  NUTRIENTS 

Energy  in 
Calories 
per 
Pound 

Average 
Cost 
per 
Pound 

Pro- 
tein 

Starch 

Other 
Carbo- 
hydrate 

Fat 

Water 

Min- 
eral 

Bread  (White) 

8. 

47. 

3. 

1. 

37. 

2. 

1280. 

$.04 

Flour 

11. 

66. 

4.2 

2. 

15. 

1.7 

1645. 

.025 

Oatmeal 

12.6 

58. 

5.4 

5.6 

15. 

3. 

1850. 

.05 

Rice 

6. 

79. 

0.4 

0.7 

13. 

0.5 

1630. 

.07 

Beans 

23.1 

55. 

2. 

2. 

12.6 

3.1 

1615. 

.05 

Potatoes 

2. 

18. 

3. 

0.2 

76. 

0.7 

375. 

.0125 

Milk 

4. 

— 

5. 

4. 

86. 

0.8 

325. 

.035 

Cheese 

28.3 

— 

1.8 

35.5 

30.2 

4.2 

2070. 

.16 

Beef  (Round) 

20.5 

— 

— 

10.1 

68.2 

1.2 

805. 

.14 

Beef  (Corned  Flank) 

14.2 

— 

—  . 

33. 

49.8 

3. 

1655. 

.10 

Mutton  (Leg) 

18.3 

— 

— 

19. 

61.8 

0.9 

1140. 

.18 

Veal  (Shoulder) 

20.2 

— 

— 

9.8 

68.8 

1.2 

79.0. 

.20 

Pork  (Shoulder—  Fresh) 

16. 

—  . 

— 

32.8 

50.3 

0.9 

1680. 

.16 

Pork  (Ham) 

16.7 

— 

— 

39.1 

41.5 

2.7 

'I960. 

.16 

Pork  (Salt  Fat) 

0.9 

— 

— 

82.8 

12.1 

4.2 

3510. 

.12 

Chicken 

24.4 

— 

— 

2. 

72.2 

1.4 

540. 

.20 

Eggs 

14.9 

— 

— 

10.5 

73.8 

0.8 

721. 

.18 

Butter 

1. 

— 

0.5 

85. 

10.5 

0.3 

3615. 

.30 

Codfish 

15.8 

— 

— 

0.4 

82.6 

1.2 

310. 

.08 

Mackerel 

18.2 

— 

— 

7.1 

73.4 

1.3 

640. 

.12 

Oysters 

6. 

— 

3.7 

1.2 

87.1 

2. 

230. 

.25 

DIETARY  STANDARDS 


CONDITIONS 

PROTEIN 

CARBO- 
HYDRATES 

FAT 

CALORIES 

Man  with  light  muscular  exercise 
Man  with  moderate  muscular  ex- 
ercise.                 

0.22  Ibs. 
0.28  Ibs. 

0.88  Ibs. 
0  99  Ibs. 

0.22  Ibs. 
0.28  Ibs. 

2980. 
4520 

Man  with  active  muscular  work 

0.33  Ibs. 

01.  10  Ibs. 

0.33  Ibs. 

4060. 

1  More  extensive  tables  may  be  found  in  a  pamphlet  printed  by  the 
Department  of  Agriculture,  Farmer's  Bulletin  No.  23,  "  Foods,  Nutritive 
Value  and  Cost,"  by  W.  O.  Atwater.  See  also  Bulletin  No.  13,  Series  I, 
March,  1909,  of  the  American  School  of  Home  Economics. 


40  EXPERIMENTAL   PHYSIOLOGY 

Questions  to  be  answered  from  study  of  Food  Chart. 

Fat  and  carbohydrates  are  the  energy  producers:  how 
does  the  table  show  this?  What  sorts  of  foods  are  richest 
as  protein  furnishers  (tissue  builders)?  Of  the  animal  and 
vegetable  foods,  which  are  richest  in  protein?  fat?  carbo- 
hydrates? 

Calculate  the  cost,  amount  of  energy  in  calories,  and  per 
cent  of  nutrients,  in  the  following  daily  dietaries: 

(a)  13  ounces  of  beef  (round),  3  ounces  of  butter,  6  ounces 
of  potatoes,  22  ounces  of  bread. 

(6)  4  ounces  of  salt  pork,  2  ounces  of  butter,  16  ounces 
of  beans,  8  ounces  of  bread. 

(c)  10  ounces  of  beef  (corned),  1  ounce  of  butter,  16  ounces 
of  milk  (pint). 

Make  up  a  suitable  daily  dietary  for  each  of  the  three 
different  classes  of  men  given  in  the  table. 


HISTOLOGICAL  STUDIES 


XXV. —  PARTS  OF  A  CELL 

Apparatus.  —  Scalpel,  compound  microscope  l  with  two-thirds  and 
one-sixth  inch  objectives  and  one  inch  ocular,  glass  slides  and  cover 
glasses,  pieces  of  filter  paper,  methyl  green  or  Delafield's  ha3ma- 
toxylin.2 

Directions.  —  Sterilize  the  scalpel  by  holding  it  in  boiling 
water,  then  scrape  the  inside  of  the  cheek  lightly  with  the 


Fia.  12. — A,  diagram  of  a  cell;  w,  cell  wall  with  enclosed  cytoplasm;  n,  nucleus, 
consisting  of  nuclear  membrane  inclosing  granular  substance,  in  which  are  seen  a 
spherical  nucleolus  and  irregular  masses  of  chromatin;  a,  centrosome;  B-F,  changes 
that  take  place  during  cell  division. 

blade.  When  the  scalpel  is  removed  from  the  mouth  there 
will  appear  on  it  the  scrapings  in  the  form  of  a  white  sedi- 
ment. Remove  a  little  of  this  sediment  and  mount  in  a 

1  Bausch  &  Lomb  and  the  Spencer  Lens  Company  furnish  at  request 
a  pamphlet  describing  all  the  parts  of  the  microscope  and  the  method 
of  handling  the  instrument. 

2  For  the  preparation  of  these  stains  consult  any  manual  of  microscopy. 
Lee's  "Vade  Mecum"  or  Guyer's  "Animal  Micrology"is  recommended. 

41 


42  EXPERIMENTAL  PHYSIOLOGY 

drop  of  water  on  the  slide.  Cover  with  the  cover  slip  and 
examine  with  the  two-thirds  objective  (low  power).  In 
focusing,  the  best  results  are  obtained  if  nearly  all  the  light 
is  excluded  by  the  diaphragm. 

Draw  what  you  see.  Note  that  the  masses  are  made  up 
of  separate  elements  (cells).  Compare  with  Fig.  12,  A. 
Are  the  walls  circular,  as  in  the  figure? 

Place  a  drop  of  the  methyl  green  at  one  side  of  the  cover 
slip  and  by  placing  the  filter  paper  at  the  opposite  side  draw 
this  solution  under  the  slip.  Let  the  slide  stand  for  a  mo- 
ment and  examine  again  with  the  low  power.  What  part 
of  the  cell  has  changed  color?  (This  part  is  called  the  nu- 
cleus of  the  cell.) 

Now  focus  on  one  of  these  cells  with  the  one-sixth  ob- 
jective (high  power).  Has  the  cell  a  definite  outline?  Note 
the  clear  liquid  between  the  nucleus  and  the  outline.  Do 
you  notice  any  particles  floating  in  this  liquid?  Draw  this 
cell,  magnified  to  an  inch  diameter,  and  label  as  follows:  the 
outside  boundary  or  cell  wall;  the  clear  liquid  or  protoplasm; 
the  particles  floating  in  this  protoplasm,  or  granules;  the 
nucleus. 

XXVI.  —  STUDY  OF  A  PLANT  CELL 

Apparatus.  —  Pond  scum  (Spirogyra),  physiological  salt  solution,1 
materials  described  in  Ex.  XXV. 

Directions.  —  Mount  a  little  of  the  pond  scum  in  a  drop 
of  water  and  cover  with  a  glass.  Examine  with  the  low 
power.  Do  you  see  any  separate  units  in  this  case?  How 
are  they  arranged?  What  is  their  color?  Is  this  color 
evenly  distributed  throughout  the  cell  or  located  in  definite 

1  Physiological  salt  solution  is  made  by  adding  6  grams  of  common 
salt  (NaCl)  to  1  liter  (1000  c.c.)  of  distilled  water. 


HISTOLOGICAL   STUDIES  43 

parts  of  the  cell?  Can  you  see  any  cell  wall?  protoplasm? 
nucleus?  Make  a  drawing  of  what  you  see  and  label  in  such 
a  way  as  to  answer  the  above  questions. 

Now  add  a  little  of  the  physiological  salt  solution,  to  be  run 
under  the  cover  glass,  and  examine  with  the  high  power.  Do 
you  see  any  nucleus  now?  any  protoplasm?  What  has  hap- 
pened to  the  protoplasm?  Draw  and  label  such  parts  of 
the  cell  as  show.  A  little  methyl  green  or  Delafield's  hsema- 
toxylin  added  will  make  the  nucleus  more  distinct. 

Make  a  list  of  the  differences  and  similarities  between  the 
cells  examined  in  Ex.  XXV  and  Ex.  XXVI. 

NOTE.  —  The  comparison  of  cells  should  be  further  demonstrated 
with  other  materials  by  the  instructor,  until  the  essential  and  varia- 
ble components  are  clearly  grasped  by  the  pupil.  Some  suggested 
material:  Pleurococcus,  potato,  diatoms,  root  tips,  etc. 

XXVII.  —  STUDY  OF  LIVING  PROTOPLASM  —  AMOEBA 

Apparatus.  —  About  a  month  beforehand  collect  the  leaves  and 
sediment  from  pools  of  still  but  clear  water.  Distribute  this  mate- 
rial —  together  with  a  few  water  plants  (Nitella  or  Chara)  —  in  sev- 
eral open,  shallow  dishes.  Keep  covered  with  water.  When,  in 
course  of  time,  the  water  in  these  has  become  clear  and  free  from 
scum,  take  up  with  a  pipette  (medicine  dropper)  some  of  the  sedi- 
ment from  the  very  surface  of  the  leaves.  Examine  this  for  amoebae 
with  the  low  power  (two-thirds  objective).  When  the  dish  contain- 
ing them  in  quantity  is  located,  mark  this  for  supply.1  The  other 
apparatus  is  the  same  as  in  Ex.  XXV. 

1  A.  W.  Weysse  of  Boston  University  gives  in  "  Science,"  Vol.  XX,  No. 
515,  the  following  method  of  securing  amoeba.  Collect  a  considerable 
number  of  lily  pads.  Remove  with  a  spatula  the  slime  which  adheres  to 
the  lower  surface  and  put  it  in  a  shallow  glass  aquarium  containing  water 
six  or  eight  centimeters  deep.  Place  the  vessel  near  a  window,  and  in  a 
week  or  two  amoebae  will  be  abundant  on  the  surface  of  the  sediment  at 
the  bottom. 


44  EXPERIMENTAL   PHYSIOLOGY 

Directions.  —  Mount  some  of  the  amoebae  on  a  glass  slide 
and  cover  them  with  a  cover  slip.  Locate  one  of  the  animals 
with  the  low  power  and  then  focus  on  it  with  the  high  power 
for  careful  observation. 

Watch  the  amoeba  until  it  begins  to  show  movement,  then 
draw  and  note  the  following  parts:  round,  opaque  nucleus, 
the  clear  outer  part  (ectoplasm)  and  the  granular  inner  part 
(endoplasm)  of  the  cytoplasm.  (Cytoplasm  is  the  name  given 
to  that  part  of  the  protoplasm  which  is  not  nuclear,  since 
the  nucleus  is  also  composed  of  protoplasm.)  Note,  further, 
the  round  spots  in  the  cytoplasm  (vacuoles:  food  vacuoles, 
water  vacuoles,  or  contractile  vacuoles,  according  to  con- 
tents); the  constantly  forming  projections  of  the  cytoplasm 
(pseudopodia) ;  and  the  absence  of  any  cell  wall. 

(Amoeba  is  a  one-celled  animal  made  up  of  free  protoplasm, 
and  hence  well  suited  to  show  the  properties  of  this  sub- 
stance, which  is  the  physical  basis  of  all  life.) 

Properties  of  Protoplasm 

A.  What  color  is  the  cytoplasm?     Does  it  appear  thicker 
or  thinner  than  the  water?     Is  the  part  containing  granules 
of  the  same  color  as  the  clear  part?     Does  this  cytoplasm 
mix   with    the   water?      Describe    the    appearance   of  the 
nucleus. 

B.  Movement.     Watch  the  moving  amoeba.     Note  the  va- 
rious steps  in  the  forming  of  a  pseudopodium.     Is  the  move- 
ment of  the  animal  rapid?     Does  it  appear  to  move  in  a 
definite  direction  or  at  random?     Do  the  particles  in  the 
water  appear  to  affect  its  movement?     Press  on  the  cover 
glass  with  a  needle  point  just  above  the  amoeba.     How  does 
the  amoeba  react?     Note  that  the  movement  of  the  amoeba 
is  produced  as  a  result  of  two  properties  of  protoplasm, 


HISTOLOGICAL   STUDIES 


contraction    and    expansion.      A    substance    showing   these 

properties  when  it  is  stimulated  is  said  to  have  contractility. 

C.   In  B  we  noted  that  the  animal  contracted  and  ex- 


FIG.  13.  —  A,  Amoeba  proteus:  a,  food  vacuole;  c,   contractile  vacuole;  ec,  ectoplasm; 
en,  endoplasm;  n,  nucleus;  v,  water  vacuoles.      B,  Amoeba  radiosa. 

panded  without  apparent  cause  in  some  cases.  We  noted 
also  that  under  pressure  it  contracted  more  strongly.  This 
power  to  respond  to  special  stimuli  is  called  irritability. 
Test  the  irritability  of  the  protoplasm  toward  heat  by  ap- 
plying the  flame  of  an  alcohol  lamp  gently  to  the  end  of 


46  EXPERIMENTAL   PHYSIOLOGY 

the  glass  side.  Record  your  observations  as  the  heat  grad- 
ually increases.  Other  tests  may  be  made  by  running  solu- 
tions of  various  salts,  etc.,  under  the  slide. 

D.  Feeding  Habits.     Examine  the  contents  of  some  of  the 
vacuoles  and  state  your  conclusions  as  to  the  form  of  food 
taken  in  by  the  protoplasm.     Note  and  describe  the  method 
of  engulfing  these  food  particles  and  the  forming  of  the 
vacuole.     Compare  several. of  these  vacuoles  as  to  the  con- 
dition of  their  contents.     From  these  observations,  what  do 
you  conclude  happens  to  food  in  the  amoeba? 

(The  process  of  taking  in  food  is  called  ingestion.  The 
process  of  dissolving  ingested  food  is  called  digestion.  The 
process  of  transforming  digested  food  into  protoplasm  is 
called  assimilation.  This  last  process  is  evidenced  by  the 
decreasing  size  of  the  vacuole  after  the  food  is  dissolved.) 

E.  The  Removal  of  Wastes.     Study  the  action  of  the  large 
contractile  vacuole.     What  does  it  appear  to  contain  when 
expanded?     Where  does  this  substance  come  from?     Where 
does  it  go  when  the  vacuole  is  contracted?     Does  the  vacuole 
pulsate  regularly? 

(The  process  of  collecting  the  broken-down  waste  of  the 
body  and  its  removal  to  the  outside  is  called  excretion. 
The  processes  described  in  D,  by  means  of  which  pro- 
toplasm is  made,  are  spoken  of  collectively  as  anabolism. 
The  processes  by  means  of  which  old  protoplasm  is  broken 
down  and  removed  are  spoken  of  collectively  as  katabolism. 
Metabolism  is  the  simultaneous  occurrence  of  these  two  ac- 
tions in  a  living  body  of  protoplasm.) 

F.  Place  several  amoebae  in  a  drop  of  water  in  a  vial  and 
cork  the  vial  tightly.     The  water  used  should  be  rich  in 
food  —  bacteria.     Also,  for  comparison,  make  a  balance  prep- 
aration consisting  of  the  same  number  of  amoebae  mounted 


eer 


in  the  same  amount  of  water  in  a  watch  glass,  this  prepara- 
tion to  be  exposed  to  the  air  in  a  large  vessel  containing  a 
little  water  to  prevent  evaporation.  Examine  at  the  end 
of  a  few  days.  What  evidence  have  you  that  protoplasm 
requires  air? 

(It  is  the  oxygen  in  the  air  that  the  animal  uses.  This 
property  of  taking  in  air  and  oxygen  is  part  of  a  process 
called  respiration.) 

Make  a  list  of  all  the  properties  of  protoplasm  as  exhib- 
ited by  the  cytoplasm  of  the  amoeba. 

XXVIIL  —  EPITHELIAL  TISSUE  (OPTIONAL) 

Apparatus.  —  Prepared  slide1  of  cross  section  of  the  small  intes- 
tine (human  preferred,  but  rat's  or  other  mammars  will  serve),  com- 
pound microscope. 


FIQ.  14.  FIG.  15. 

Epithelial  Tissues,     a,  two  forms  of  epithelial  tissue:   1,  columnar;   2  and  3,  squamous; 
c,  stratified  tissue;  6,  simple  ciliated  tissue;  d,  ciliated  columnar  tissue. 

Directions.  —  Focus  with  the  high  power  on  the  cells 
forming  the  inner  layer  of  the  intestine.  Draw  six  or  eight 

1  Prepared  slides  for  study  of  tissues  may  be  bought  best  of  dealers,  as 
their  preparation  is  a  matter  of  delicacy  and  skill.  For  those  who  wish  to 
prepare  their  own,  suitable  directions  will  be  found  in  standard  histologies, 
such  as  Stohr's  or  Schafer's,  and  in  Lee's  "  Vade  Mecum  "  or  Guyer's 
"Animal  Micrology." 


48 


EXPERIMENTAL   PHYSIOLOGY 


of  these  cells,  showing  the  large  nucleus  in  each,  the  general 
outline  of  the  cells,  and  the  distribution  of  the  protoplasm. 
Note  the  thinness  of  the  cell  wall  and  the  absence  of  inter- 
cellular material.  Compare  these  cells  (columnar  epithelium; 
see  Fig.  15,  d)  with  those  of  Ex.  XXV  (squamous  epithelium; 
see  Fig.  14,  a,  2  and  3,  and  c).  How  do  they  differ?  Note 
the  protective  character  of  these  layers  of  cells  with  reference 
to  the  underlying  layers.  (One  feature  of  this  protection  is 
prevention  of  the  action  of  digestive  fluids  upon  the  under- 
lying muscles  and  other  forms  of  tissue.) 

XXIX. —  CONNECTIVE  TISSUE  (OPTIONAL) 

Apparatus.  —  Prepared  slides  of  intermuscular  tissue,  cartilage, 
and  bone,  compound  microscope. 

Directions.  —  A.    Intermuscular  Tissue.    Draw,  under  the 
low  power.     Note  two  classes  of  bundles  of  fibers   (white 

fibers  and  elastic).  The  elastic 
fibers  are  single  and  are  more 
sharp  in  outline  than  the  white. 
Find  one  of  the  cells  (or  corpus- 
cles) and  focus  with  the  high 
power.  Draw  it,  and  show  in  your 
drawing  its  relation  to  the  two 
classes  of  fibers.  From  your 
study,  which  part  of  this  tissue . 
should  you  say  was  most  impor- 
tant, the  cellular  part  or  the  in- 
tercellular fibers? 

B.  Cartilage  (hyaline).  Note 
the  solid  character  of  the  inter- 
cellular matrix,  the  outlines  of  the  cells  with  their  proto- 
plasm and  'nucleus,  the  lacunce,  or  pits  in  which  the  cells 


Bundle  of  White  Fibers 
FIG.  16. — Intermusoular  Tissue. 


HISTOLOGICAL   STUDIES 


49 


lie,  and  the  capsules  inclosing  these  lacunae.  Which  part  of 
this  tissue  is  supporting,  the  cells  or  the  matrix?  Draw 
a  section,  under  the  high 
power,  and  label  all  parts. 

C.  Bone.  Note  the  ma- 
trix of  spongy  bone  arranged 
in  concentric  rings  (lamellae) 
around  the  central  canals 
( Haversian  canals) .  Between 
the  lamellae  note  the  irregu- 
lar cavities  lacunce)  with 
their  wavy  branches  or  cana- 
liculi.  Note  how  these  ca- 
naliculi  connect  the  lacunae 
with  one  another  and  with 
the  Haversian  canals.  Look  in  the  lacunae  for  the  bone  cells. 


cop.  — 


Fio.  17. —  Hyaline  Cartilage:  cap,  capsule; 
m,  matrix  formed  by  cells;  c,  cartilage 
cell;  n,  nucleus. 


Fia.  18.  —  Bone:  a,  canaliculi;  b,  Haversian  canal;  c,  lacuna. 

(In  ground  sections  of  bone  these  will  probably  be  wanting. 
They  appear  better  hi  sections  of  decalcified  bone.)     Draw, 


50 


EXPERIMENTAL   PHYSIOLOGY 


under  high  power,  a  section  locating  all  the  above-named 
parts. 

(Note  in  the  three  classes  of  connective  tissue  that  the 
intercellular  portion  is  the  important  part  in  support.  The 
importance  of  the  cells  becomes  clear  when  it  is  understood 
that  this  intercellular  matrix  is  produced  by  them.) 

XXX.  —  MUSCULAR  TISSUE  (OPTIONAL) 

Apparatus.  —  Prepared  slides  of  striated  and  non-striated  muscle, 
compound  microscope. 

Directions.  —  A.  Non-striated.  Note  the  long,  spindle- 
shaped  cells,  the  elongated  nucleus,  and  the  homogeneous 

protoplasm  filling  the  whole 
cell.  Note,  further,  how  these 
FIQ.  19.  —  A  Non-striated  Muscle  Ceil;  n,  cells  interlace.   (They  are  held 

together    by  a  homogeneous 

cement  substance.)  Note  the  absence  of  any  striation,  or 
striping.  Draw  several  of  these  cells  under  the  high  power, 
locating  all  the  parts  mentioned  above. 

B.  Striated.  Examine  a  single  fiber  with  the  high  power. 
Note  the  broad,  dim,  transverse  striae  and 
the  narrow,  light,  transverse  striae.  The 
broad  stria  is  called  anisotropic  or  doubly 
refracting,  contractile  sarcoplasm.  The  nar- 
row stria  is  called  isotropic  or  singly  refract- 
ing sarcoplasm.  Note  also  the  more  or  less 
dim  longitudinal  striation.  Over  the  whole 

FIG.  20. —  Portions  of 

of  the  fiber  is  stretched  the  transparent  striated  Muscle 
sarcolemma,  or  cell  wall.  Somewhere  on  Fibers.  (The  figure 

shows      the      striae 

the  fiber  may  be  found  also  several  nuclei.      and  the  nuclei. ) 
Draw  and  locate  all  these  parts  of  the  muscle  cell.     (Sar- 
coplasm is  merely  another  name  for  the  protoplasm  of  a 
muscle  cell.) 


v 


HISTOLOGICAL    STUDIES 


XXXI.  —  NERVOUS  TISSUE  (OPTIONAL) 


51 


Dendrites 


Nerve  process 


Axis  cylinder 


Neurilemma 


Apparatus.  —  Prepared  slides  of  ganglion  cells  and  nerve  fibers,1 
compound  microscope. 

Directions.  —  A.    The    Nerve         . 
Cell.     Note  the  irregular  outline    °  y 
of   the    cell;    the  wavy  projec- 
tions, or  dendrites;  the  rodlike 
projections,   or    nerve  processes. 
Note  the    position    of   the  nu- 
cleus.     Has    the    cell    one    or 
more    nerve    processes?     Draw 
and  locate  all  parts,  under  the 
high  power. 

B.  The  Nerve  Fiber.  Make 
out  from  your  study  of  the 
nerve  fiber  the  axis  cylinder 
in  the  center.  (This  corre- 
sponds to  the  nerve  process  of 
A.)  Next  outside  this  is  the 
medullary  sheath,  and  on  the 
very  outside  the  neurilemma. 
Make  a  drawing  showing  all 
these  parts.  For  their  relation 
compare  with  Fig.  21. 

All  tissues  of  the  body  can 
be  placed  in  one  of  the  above 
classes,  —  epithelial,  connective, 
muscular,  or  nervous. 

1  A  smear  preparation  of  spinal  cord  may  be  prepared  as  follows :  Rub  a 
piece  of  fresh  spinal  cord  in  water  between  two  cover  glasses.  Mount  and 
run  under  the  cover  glass  a  drop  of  methyl  green.  Both  nerve  fibers  and 
nerve  cells  appear  in  such  a  preparation. 


Terminal 
branches 


FIG.  21. — Scheme  of  a  Neuron:  a, 
free  axis  cylinder;  6,  axis  cylinder 
surrounded  by  neurilemma  alone; 
c,  axis  cylinder  surrounded  by 
medullary  sheath  alone;  d,  axis 
cylinder  surrounded  by  the  sheath 
and  neurilemma  and  divided  into 
segments  (by  constrictions  called 
the  nodes  of  Ranvier). 


PRINCIPLES  OF  DIGESTION 


XXXII.  —  PRINCIPLES  OF  OSMOSIS. 


Apparatus.  —  Potassium  bichromate,  glucose,  white  of  egg,  starch, 
beet  root,  Fehling's  solution,  iodine  solution,  Millon's  reagent,  dialyzer. 
There  are  several  forms  of  dialyzer  described  by  different  authors, 
any  one  of  which  will  serve.  (1)  The  following  form  has  been 

found  very  satisfactory :  Take  ordinary 
collodion  and  a  glass  beaker.  Pour  the 
collodion  into  the  beaker  and  then  pour 
out  again,  revolving  the  beaker  so  as  to 
bring  the  collodion  into  contact  with 
the  entire  inner  surface  of  the  glass. 
Let  the  beaker  drain  for  a  few  mo- 
ments. The  ether  will  evaporate  and 
leave  a  thin  skin  on  the  inside  of  the 
beaker.  As  soon  as  the  skin  is  tough 
enough,  loosen  it  at  the  top  and  pour 
water  between  it  and  the  glass.  With 
care  the  entire  skin  will  separate  from 
the  glass,  giving  a  membranous  bag 
which  is  exactly  the  shape  of  the  beaker, 
is  water  tight  and  ideal  for  these  ex- 
periments. Any  shape  bag  may  be 
obtained  by  selection  of  the  receptacle. 
(2)  Obtain  from  the  butcher  some  skins 
such  as  are  used  to  hold  sausage  meat. 
Tie  one  of  these  around  the  base  of  a 
student  lamp  chimney,  as  in  Fig.  22,  after  cutting  off  the  chimney  so 
that  it  is  only  about  six  inches  in  height.  Select  a  cork  to  fit 
tightly  in  the  top  of  the  chimney  and,  with  a  cork  borer,  puncture 
this  to  fit  an  eighth-inch  glass  tube  about  a  foot  in  length.  Arrange 
the  whole  apparatus  as  in  the  diagram,  supporting  the  chimney  in 
an  outer  jar  so  that  it  will  not  rest  on  the  bottom.  To  fill  the 

52 


FIG.  22. 


PRINCIPLES  OF   DIGESTION 


53 


chimney,  remove  the  cork  and  tube.    The  tube  will  serve  as  a  deli- 
cate indicator  of  the  amount  of  rise  in  the  water. 

Directions.  —  A.  Put  into  the  dialyzer  some  crystals  of 
potassium  bichromate.  Fill  with  water  both  the  dialyzer 
and  the  outer  jar  until  the  level  is  the  same  in  each.  Allow 
them  to  stand  for  a  short  time.  Then  examine  and  note  the 
level  of  water  in  the  two  parts.  What  has  been  the  pre- 
vailing direction  of  flow  of  water?  Is  the  color  of  the  water 
in  the  outer  jar  changed?  Has  some  of  the  salt  solution  in 
the  dialyzer  passed  through  the  membrane?  (This  inter- 
change of  water  and  salt  solution  through  a  membrane  — 
the  sausage  skin  or  the  collodion  —  is  called  osmosis.) 

B.  Place  some   glucose  in  a  beaker  with  some  water. 
When  the  grape  sugar  is  well  dissolved,  transfer  this  liquid 
to  the  dialyzer.     Fill  both  dialyzer  and  outer  jar  to  the  same 
level  with  water  as  before.     Note  the  direction  of  the  water- 
flow.  Test  the  water  in  the 

outer  jar  with  Fehling's 
solution.  What  results? 
Does  grape  sugar  in  solu- 
tion pass  readily  through 
the  membrane?  (Sub- 
stances which  pass  readily 
in  solution  through  a 
membrane  under  the  FlQ.23._^  living  cell;  Bt  cell  whoge  proto. 

above    Conditions  may  be       plasm    has    been    killed    by    boiling;    cw,   cell 
.  -,    ,  N  wall;  n,  nucleus;  p,  protoplasm. 

said  to  osmose.) 

C.  Substitute  for  the  glucose  solution"  a  diluted  starch 
paste.     After  a  time  note  the  level  of  the  water.     Record 
its  direction  of  flow.     Test  the  liquid  in  the  outer  jar  with 
iodine  solution.     Does  starch  osmose?    Does  starch  crystal- 
lize like  grape  sugar  and  potassium  bichromate? 


54  EXPERIMENTAL   PHYSIOLOGY 

D.  Substitute  for  the  starch  paste  a  solution  made  of 
white  of  egg  whipped  up  in  water.     Note  direction  of  flow 
of  water.     Test  the  water  in  the  outer  jar  with  Millon's 
test  for  proteid.     Does  egg  albumin  osmose? 

E.  Cut  a  few  slices  of  beet  root.     Wash,  and  place  a  few 
pieces  in  two  separate  beakers.     Fill  each  beaker  half  full 
of  distilled  water.     Boil  the  slices  in  one  of  the  beakers. 
(This  kills  the  protoplasm  in  the  cells  of  the  beets  without 
injury  to  the  cell  walls.)     Add  a  few  drops  of  hydrochloric 
acid  to  each  beaker,  and  then  test  with  Fehling's  solution 
for  grape  sugar.     In  which  has  the  sugar  dialyzed  from  the 
cells?     In  which  is  the  water  colored?     Study  tne  arrange- 
ment of    protoplasm  in  a  dead    and    in   a  living    cell,   as 
illustrated  in  Fig.  23,  and  state  your  conclusions  as  to  the 
influence  of  protoplasm  on  osmosis. 

(Substances    that    osmose    are    called    crystalloids.     Sub- 
stances that  do  not  osmose  are  called  colloids.) 

F.  Make  a  mixture  of  grape  sugar,  white    of  egg,  and 
water.      Put   in  the  dialyzer  with  water   on  the   outside. 
After  a  time  test  the  water  with:   (a)  Benedict's  or  Feh- 
ling's solution.    Result?    (6)  Biuret  reagent.     Result?    Sep- 
aration of   crystalloids  from  colloids  by  osmosis   is   called 
dialysis. 


f 


'(flP 


XXXIII.  —  AN  ENZYME 


Apparatus.  —  Ground  malt,  starch,  test  tubes,  iodine  solution, 
Fehling's  solution. 

Directions.  —  Make  an  extract  of  malt  diastase  (an  en- 
zyme) by  shaking  up  five  grams  of  ground  malt  with  50  c.o. 
of  cold  water.  Let  it  stand  for  a  few  hours  and  then  filter. 
Make  a  thin  starch  paste  by  mixing  a  teaspoonful  of  starch 


PRINCIPLES   OF   DIGESTION  55 

with  a  cup  of  boiling  water.1  Fill  two  test  tubes  half  full 
of  this  starch  preparation.  Test  a  little  of  the  starch  prep- 
aration with  the  iodine  solution,  to  determine  strength  of 
reaction.  Test  a  little  of  the  starch  preparation,  and  also 
some  of  the  diastase  solution,  with  Fehling's  solution.  Is 
grape  sugar  present  in  either  of  them?  Now  add  10  c.c. 
of  diastase  solution  to  one  of  the  test  tubes;  warm  both 
tubes,  and  keep  them  as  near  as  possible  at  a  constant 
temperature  of  45  C. 

At  intervals  of  five  minutes  remove  a  little  of  the  con- 
tents of  each  tube  with  a  pipette  and  test  with  the  iodine 
solution.  Do  the  same-,  using  Fehling's  solution  instead  of 
iodine  solution.  Is  the  amount  of  starch  on  the  increase  or 
the  decrease  in  either  tube?  After  how  long  a  time  do  you 
get  a  test  for  grape  sugar,  and  in  which  tube?  Continue 
these  tests  until  you  get  a  strong  test  for  grape  sugar. 

(The  reason  for  these  results  is  that  the  malt  diastase  — 
the  enzyme  —  is  slowly  changing  the  starch  into  sugar.  An 
enzyme  is  a  substance  which  can  bring  about  the  trans- 
formation of  one  chemical  compound,  such  as  starch,  into 
another,  such  as  sugar,  without  itself  being  used  up.  The 
value  of  enzyme  action  in  our  bodies  lies  in  the  fact  that 
by  it  a  colloid,  like  starch,  may  be  changed  into  a  crystalloid, 
like  sugar,  which  can  then  be  absorbed  through  a  membrane 
by  osmosis,  e.g.,  from  the  stomach  through  the  walls  of  the 
blood  vessels  into  the  blood.) 

1  To  make  clear  starch  paste,  free  of  lumps,  first  have  the  water 
boiling  vigorously.  Then  mix  the  starch  with  a  little  cold  water, 
shaking  to  get  a  milky  fluid.  Now  add  the  milky  fluid,  a  drop  at  a 
time,  to  the  boiling  water.  Stir  constantly  while  adding  the  starch. 
This  paste  may  be  kept  for  a  considerable  time  by  adding  a  little  pow- 
dered thymol. 


EXPERIMENTAL   PHYSIOLOGY 

XXXIV.  —  A  FERMENT  ORGANISM  —  YEAST  . 

Apparatus.  —  Yeast  cake,  molasses,  eight-ounce  bottle,  absorbent 
cotton,  limewater,  chemical  thermometer. . 

Directions.  —  Dissolve  a  piece  of  yeast  cake,  the  size  of 
a  pea,  in  two  tablespoonfuls  of  water.  Pour  this  into  the 
eight-ounce  bottle.  Add  to  this  a  tablespoonful  of  mo- 
lasses and  fill  the  bottle  half  full  of  water.  Stopper  with 
a  plug  of  absorbent  cotton  and  leave  in  a  warm  place  for 
twenty-four  hours.  Record  the  temperature  of  the  room  /V 
in  which  the  bottle  is  put  and  the  temperature  of  the 
mixture,  ty* 

At  the  end  of  the  twenty-four  hours  remove  the  stopper 
and  examine  the  contents.  What  is  the  temperature? 
Does  it  smell  sweet?  Test  the  gas  in  the  top  of  the  bottle 
with  a  drop  of  limewater.  What  gas  gives  this  reaction?3?v 
Does  the  odor  give  you  any  evidence  of  the  presence  of 
alcohol?  Examine  under  the  low  power  of  the  compound 
microscope  a  little  of  the  sediment  from  the  bottom  of  the 
bottle,  mounted  in  water.  Draw  several 
groups  of  the  separate  elements  of  this 
sediment.  (These  bodies  are  yeast  plants.) 
(Yeast  is  a  one-celled  plant  that,  with- 
out changing  its  yeast  character,  is  capable 
of  transforming  sugar  into  carbon  dioxide 
and  alcohol.  In  its  power  to  change  a 

Flo  24. Yeast  Plants:  substance,  without  itself  undergoing  trans- 

i,  a  plant  forming  a  formation,   it   acts   like    an   enzyme,   and 

bud;   2,  the  bud  near- 
ly ready  to  separate  hence  is  called  a  ferment  organism.      The 

as  a  new  plant.  yeast  cell  in  growing  actually  secretes  an 

enzyme  which  produces  this  change.     Hence  a  "  ferment  or- 
ganism "  is  simply  a  cell  or  collection  of  cells  which  secrete 


PRINCIPLES   OF   DIGESTION 


57 


enzymes.  Many  digestive  actions  are  performed  by  en- 
zymes. Most  enzymes  are  produced  in  the  body  by  the 
cells  of  organs  called  glands.) 


<XXXV.  —  STRUCTURE  OF  A  TYPICAL  GLAND. 

Apparatus.  —  Microscope  and  accessories  used  in  the  study  of 
tissues,  prepared  slide  of  crypt  of  Lieberkuhn  from  the  small  intestine 
of  man.  (Any  other  gland  preparation  will  serve.) 

Directions.  —  Examine  first  with  the  low  power.  Draw 
the  entire  gland  and  note  the  following  points:  the  kind  of 
tissue,  the  arrangement  of  the  cells,  the  gland  lumen,  or 


FIG.  25. —  A  Salivary  Gland;  a,  lumen 
of  a  gland  in  longitudinal  section;  b,  a 
gland  in  cross  section;  c,  connective 
tissue. 


Fia.  26. —  Forms  of  Glands. 


central  cavity.  With  the  high  power  examine  a  few  of  the 
cells  and  their  contents.  Draw,  and  note  the  position  of 
the  nucleus,  the  protoplasm,  and  the  secretion  in  various 
cells.  Fig.  26  illustrates  the  relation  of  the  simple,  tubular 
gland,  such  as  you  have  just  studied,  to  the  compound  forms. 


ORGANS  AND  PROCESSES  OF  DIGESTION 


XXXVI.  —  DISSECTION  OF  A  RAT'S  DIGESTIVE  ORGANS 

Apparatus. —  Rat,1  dissecting  tray  with  wax  lining,  scissors,  for- 
ceps, bristle  probes,  10  %  alcohol  or  1  %  formalin. 

Directions.  —  Lay  the  rat  on  its  back  in  the  tray,  stretch, 
and  tie  or  pin  the  legs  as  in  the  diagram.     Cover  with  10  % 

alcohol  or  1  %  formalin. 

Locate  the  lower  end  of 
the  breast  bone  and  slit  the 
skin  from  this  point  to  the 
anus.  On  each  side,  at  the 
middle  point  of  the  slit, 
make  a  slit  at  right  angles. 
Turn  back  the  four  flaps 
and  pin  them. 

Note  the  thin  membrane 
(peritoneum)  lining  the  ab- 
domen. Is  it  flexible?  Re- 
move this  and,  without  dis- 
t  u  r  b  i  n  g  the  underlying 
FIG.  27.  parts,  locate  the  stomach, 

the  liver,  and  the  coiled  intestine. 

Press  the   intestine   downward   and   determine  the  size, 
position,  shape,  and  color  of  the  stomach.     Find  the  ends 

1  This  exercise  may  be  made  a  demonstration.     In  that  case  a  larger 
animal,  such  as  the  rabbit,  would  be  preferable. 

58 


ORGANS  AND   PROCESSES   OF  DIGESTION  59 

that  are  connected  with  the  intestine  (pyloric  end)  and  with 
the  esophagus,  or  gullet  (cardiac  end).  Note  the  covering 
of  blood  vessels. 

In  the  fold  of  the  intestine  (duodenum)  next  to  the  stom- 
ach, locate  the  fatty-looking  pancreas,  f  Find  its  duct  and 
trace  its  connection  with  the  duodenum. 

Press  forward  the  liver  and,  on  its  posterior  surface,  find 
bile  sac.  Locate  the  connection  of  this  with  the  two 
lobes  of  the  liver  (the  hepatic  ducts).  Open  this  sac  and, 
with  the  probe,  find  its  connection  (the  bile  duct)  with  the 
pancreatic  duct  and  the  duodenum.  Note  that  the  bile  duct 
and  the  pancreatic  duct  fuse  and  enter  the  duodenum  by  a 
common  duct. 

-Examine  the  membrane  (mesentery)  which  supports  the 
intestine.  Note  its  blood  vessels.  Carefully  unravel  the  in- 
testine (Caution!  do  not  break  it)  from  the  stomach  to  the 
anus.  Determine  the  relative  lengths  of  the  small  and  the 
large  intestine  and  the  method  of  their  joining.  (This  con- 
nection is  guarded  by  a  valve  which  acts  in  such  a  way  as 
to  prevent  matter  returning  from  the  large  to  the  small 
intestine.) 

--Slit  the  stomach  just  below  the  gullet  entrance  and, 
with  the  probe,  find  its  connection  with  the  mouth.  Above 
the  liver  and  the  stomach,  find  the  muscular  partition 
(diaphragm)  separating  the  abdominal  from  the  thoracic 
cavity. 

Illustrate,  by  a  diagrammatic  drawing,  the  connections 
of  the  following  parts:  mouth,  gullet,  stomach,  liver,  pan- 
creas, small  intestine,  large  intestine. 

Carefully  remove  the  stomach,  liver,  pancreas,  and  intes- 
tines, and  preserve  the  rest  of  the  animal  for  further  dis- 
section in  85  %  alcohol  or  4  %  formalin. 


x 


EXPERIMENTAL   PHYSIOLOGY 

XXXVII.  —  THE  TEETH 

Apparatus.  —  A  hand  mirror,  a  molar  tooth  sawed  in  vertical  sec- 
tions, an  apple. 

Directions.  —  A.  Kinds  of  Teeth.  With  the  aid  of  the 
mirror  and  the  finger  count  the  number  of  teeth  on  each  jaw. 
Is  the  number  the  same?  Note  that  they  may  be  divided 


a 


FIG.  28. — a,  incisors;  6,  canines;  c,  premolars;  d,  molars. 

into  four  classes  according  to  shape.  How  many  broad 
teeth  (incisors)  have  you  in  the  front  of  each  jaw?  How 
many  with  one  point  on  the  surface  (canines)!  How  many 
with  two  surface  points  (bicuspids  or  premolars)!  with  more 
than  two  surface  points  (molars)!  Tabulate  these  numbers 
as  follows: 


UPPER  JAW 

LOWER  JAW 

Incisors 

Canines 

Premolars 

Molars 

Grand  Total 


PRINCIPLES   OF   DIGESTION 


61 


Examine  the  mouths  of  animals,  such  as  the  squirrel  or 
rat,  the  cat  or  dog,  and  the  horse  or  cow.  How  do  they 
differ  as  to  the  kind  and  number  of  their  teeth?  What  kind 
of  food  does  each  animal  eat?  Which  kind  of  food  requires 
the  most  chewing?  Do  you  see  any  connection  between 
the  food  and  the  kind  of  teeth  which  predominates  in  each 
animal? 

B.  Structure  of  a  Tooth.     Draw  a  section  of  a  molar  tooth. 
Find  the  following  parts:  the  crown,  the  neck,  roots  or  fangs, 
the  covering  of  the  crown  (enamel), 

the  covering  of  the  fangs  (cement), 
the  central  or  pulp  cavity  with  nerve 
and  blood-vessel  aperture,  the  mid- 
dle layer  (dentine).  Label  all  these 
parts  in  your  drawing.  Examine,  if 
possible,  the  jaw  of  a  human  skele- 
ton to  show  the  insertion  of  the  teeth 
in  it. 

C.  The   Use  of  the  Teeth.     Bite  off 
a  piece  of  apple  and  chew  it.     An- 
swer the  following  questions:    Which 
teeth  are  used  in  the  biting  off  of  the 

apple?  which  to  chew  it  into  small  pieces?  How  are  these 
latter  best  adapted  to  break  up  the  food?  Of  what  advan- 
tage is  it  that  a  horse's  molars  are  ridged  on  the  surface? 
Could  you  tell  from  the  examination  of  the  teeth  the  kind  of 
food  an  animal  eats? 

When  a  tooth  decays  what  part  actually  decays?  What 
is  the  difference  in  the  functions  of  the  enamel  and  of  the 
dentine?  How  does  the  location  of  the  nerves  in  the  pulp 
cavity  protect  them?  Why  is  a  decayed  tooth  apt  to 
ache? 


FIG.  29. — -A  Molar:  k,  crown; 
n,  neck;  /,  fangs;  e,  enamel; 
d,  dentine  enclosing  the  pulp 
cavity;  c,  cement. 


62          >0f  EXPERIMENTAL   PHYSIOLOGY 

[VIII.  —  PREPARATION  OF  DIGESTION  FLUIDS 
(OPTIONAL) 

A.  Collection  of  Saliva.     With  aid  of  a  piece  of  paraffin 
to  chew,  stimulate  the  flow  of  saliva  and  collect  in  a  small 
beaker  as  fast  as  it  forms.     Filter  this  through  a  wetted 
filter  paper  and  use  the  filtrate.     The  saliva  should  give 
no  test  with  Fehling's  or  Benedict's  solution. 

B.  Artificial  Gastric  Juice.     Obtain  a  pig's  stomach.     Cut 
it  open  and  wash  its  contents  out  by  gently  flushing  it  with 
water.     Remove  the  mucous  membrane  from  the  cardiac 
end,  and  after  drying  this  with  filter  paper  mince  it  and 
bottle  with  four  or  five  ounces  of  glycerine.     (The  glycerine 
dissolves  the  pepsinogen.)     After  three  days  filter  through 
muslin.     The    filtered    solution   may  be   kept  indefinitely. 
When  required  for  use  add  0.2  %  hydrochloric  acid  in  the 
ratio  of  10  parts  of  the  acid  to  1  part  of  glycerine  solution. 
This  acid  converts  the  pepsinogen  to  pepsin.1 

A  substitute  for  the  above  is  solid  pepsin  powder  dis- 
solved in  water.  For  use,  this  should  be  treated  with  0.2  % 
hydrochloric  acid  in  the  same  way  as  the  glycerine  solution. 

C.  Artificial   Pancreatic  Juice.     Obtain  sheep  pancreas. 
Remove  all  lumps  of  fat  and  mince  the  pancreas  thoroughly. 
Next  grind  the  minced  mass  with  a  little  sand  and  water  in 
a  mortar,  until  it  is  in  the  form  of  a  thin  paste.     Pour  this 
paste  into  a  bottle  and  add  150  c.c.  of  30  %  alcohol.     Shake 
repeatedly  and  let  stand  for  24  hours.     At  the  end  of  that 
time  strain  the  extract  through  cheesecloth  and  then  filter 
through  wet  filter  papers.     For  use  add  to  1  volume  of  the 
alcohol  extract  2  volumes  of  0.5  %  sodium  carbonate  solution. 

1  If  required  for  use  at  once,  the  membrane  may  be  extracted  with 
0.2  %  HC1  directly,  without  the  use  of  the  glycerine. 


63 

A  substitute  for  this  solution  may  be  made  by  dissolving 
the  solid  pancreatin  powder  in  water.  For  fat  digestion  add 
to  this  the  sodium  carbonate  solution  in  the  same  way  as 
to  the  pancreas  solution. 

D.  Bile.     Open  and  extract  the  contents  of  an  ox  gall 
or  dissolve  prepared  ox  gall  in  water. 

E.  Temperature  Conditions.    To  obtain  the  best  results  in 
all  artificial  digestion  experiments  keep  the  materials  used  as 
nearly  as  possible  at  a  constant  temperature.     For  this  pur- 
pose it  is  suggested  that  a  constant-temperature  water  bath 
be  used,  if  possible.     If  this  is  unavailable,  an  ordinary  dry- 
ing oven  may  be  used  with  an  Argand  burner.     Another 
substitute    is    a    deep    agate    dish,  —  such    as    is    used   in 
cookery,  —  with  the  Argand  burner.     Place  in  test  tubes 
the  fluids  and  materials   to   be   digested.     Cover  the  top 
of  the  agate  dish  with  a  wooden  cover  having  holes  bored 
to  fit  the  test  tubes,   and    suspend    the    tubes    in    these. 
Fill  the  dish  half  full   of  water  and  heat  it  to  the  tem- 
perature desired.      Adjust  the  Argand  burner  to  maintain 
just  that  temperature. 


XXXIX.  —  SALIVARY  DIGESTION 

Apparatus.  —  A  little  salt,  dry  cracker,  dilute  starch  paste,  white 
of  egg,  olive  oil,  saliva,  litmus  paper,  Fehling's  solution,  concen- 
trated hydrochloric  acid,  test  tubes,  constant-temperature  apparatus, 
dialyzer. 

Directions.  —  A.  General  Functions  of  Saliva.  Clear  the 
mouth  of  saliva  by  swallowing,  and  wipe  dry  the  top  of  the 
tongue.  Place  on  the  tongue  a  bit  of  salt.  Can  you  taste 
the  salt?  Close  the  mouth,  letting  the  salt  stay  on  the 
tongue.  What  happens  in  the  mouth?  Where  does  the 


64  EXPERIMENTAL   PHYSIOLOGY 

saliva  come  from  in  the  mouth?  Where  is  it  made?  Was 
the  presence  of  the  salt  on  the  tongue  sufficient  to  cause  its 
flow?  What  does  it  do  to  the  salt?  Can  you  taste  the  salt 
now?  Do  you  think  the  effect  would  be  the  same  if  the 
salt  had  been  dissolved  in  water?  Verify  by  placing  a 
drop  of  salt  water  on  the  dry  tongue.  Name  two  functions 
of  saliva  that  this  experiment  shows. 

Again  clear  the  mouth  of  saliva,  wipe  the  tongue  dry,  and 
place  on  it  some  powdered  cracker.  Try  to  swallow  the 
cracker.  Is  it  easily  done?  With  the  tongue  moisten  the 
cracker  with  saliva  and  try  to  swallow.  Is  swallowing  easy 
now?  What  is  another  function  of  saliva? 

Chew  some  of  the  cracker  slowly  and  note  if  any  change 
takes  place  in  its  taste.  Place  on  the  dry  tongue  some 
cracker  moistened  with  water.  Is  the  taste  the  same? 
What  power  has  the  saliva  that  is  not  due  to  its  liquid 
quality  only?  (This  last  power  of  the  saliva  is  called  its 
chemical  power  as  distinguished  from  its  purely  mechani- 
cal properties.) 

B.  Enzyme  Action  of  Saliva.     Collect  and  filter  saliva  as 
described  in   A   of  Ex    XXXVIII.     Prepare  a  little  thin 
starch  paste.     Test  a  sample  of  the  saliva  and  the  starch 
paste  with  Benedict's  or  Fehling's  solution.     If  no  grape 
sugar  is  indicated  they  are  ready  for  use.     Next  add  1  c.c. 
of  saliva  to  5  c.c.  starch  paste  in  a  test  tube  and  put  in  a 
water  bath  at  a  temperature  of  36°  Centigrade.     At  inter- 
vals of  10  minutes  test  the  mixture  with  Benedict's  or  Feh- 
ling's solution.     Results?     What  has  the  saliva  done  to  the 
starch?     What  caused  the  change  in  taste  of  the  cracker 
in  the  mouth? 

C.  Conditions  Affecting  Salivary  Digestion.     Place  in  each 
of  four  test  tubes  5  c.c.  thin  starch  paste.     Add  a  cubic 


PRINCIPLES   OF   DIGESTION  65 

centimeter  of  clear  saliva  to  each,  and  label  them  Tubes  1, 
2,  3,  4.  Pack  Tube  2  in  ice,  boil  the  contents  of  Tube  3. 
Add  a  few  drops  of  concentrated  hydrochloric  acid  to  the 
fourth  tube.  In  a  fifth  tube  place  1  c.c.  of  saliva  and  a  little 
minced  white  of  egg,  and  label  it  "  Tube  5."  In  a  sixth 
tube  place  1  c.c.  of  saliva  and  a  few  drops  of  olive  oil. 
Label  it  "  Tube  6."  Shake  each  tube.  ^L»J*y*>^^ 
|  Tube  1.  Test  the  mixture  with  litmtis  paper.  Is  it  acid 
r  pr  alkaline?  Now  heat  it  gently  to  a  temperature  of  36°  C.  €< «, 
/Keep  it  at  this  temperature  for  twenty  minutes  and  then 
test  with  Fehling's  solution.  What  has  the  saliva  done  to 
tiie  starch?  t  ^  -*r  *s*y- 

Tube  2.     After  the  second  tube  has  been  in  ice  twenty  £  ^s 

inutes,  test  with  Fehling's  solution.     What  is  the  effect  of  fl*  \ 
old  on  the  action  of  saliva? 

Tube   3.     Keep    the    third    tube    at    room    temperature  ,&  \ 
(twenty  minutes  and  test  as  above.     Note  result.     Let  stand     .*\ 
,wenty  minutes  longer  at  36°  C.  and  then  test  again  with 
'ehling's  solution.     Result?     What  has  the  boiling  done  to 
the  saliva?  ^  ) 

Tube  4.     Heat  the  fourth  tube  to  36°  C.  for  twenty  min-^/A 
f  }  utes  and  then  test  as  above.     Does  the  Fehling's  solution  §  *  ' 
;ie  any  test  for  sugar?     Reason?  ^\ 

Tube  5.    Heat  the  fifth  tube  to  36°  C.  for  twenty  minutes  '  ^  I 
and  then  test  with  Fehling;s  solution.     Does  saliva  convert    ' 
white  of  egg  to  sugar? 

Tube  6.     Treat  Tube  6  in  the  same  way  as  Tube  5.     Does 
saliva  change  olive  oil  to  sugar? 

Tabulate  conditions  favorable  and  unfavorable  to  salivary 
digestion. 

D.    Relation  of  Salivary  Digestion  to  Osmosis.     In  each  of 
two  dialyzers  place  20  c.c.  thin  starch  paste.     To  one  add 


66  EXPERIMENTAL   PHYSIOLOGY 

2  c.c.  saliva.  Surround  each  dialyzer  with  water,  and  at 
the  end  of  24  hours  test  the  water  with  Fehling's  or  Bene- 
dict's solution,  and  with  iodine  solution.  Does  starch 
osmose?  Does  grape  sugar?  What  advantage  results  to 
the  body  from  the  salivary  digestion  of  starch? 


XL.  —  PEPTIC  DIGESTION 

Apparatus.  —  Glycerine  solution  of  pepsin  or  solid  pepsin  dis- 
solved in  water,  0.2  %  hydrochloric  acid,  concentrated  hydrochloric 
acid,  caustic  soda,  alcohol,  minced  white  of  egg,  starch,  beef  fat, 
milk,  test  tubes,  constant-temperature  apparatus,  biuret  reagent, 
Millon's  reagent. 

Directions.  —  A.  Action  of  Artificial  Gastric  Juice  on  a 
Protein.  To  a  small  piece  of  white  of  egg  in  a  test  tube  add 
10  c.c.  of  artificial  gastric  juice  prepared  as  described  in 
Ex.  XXXVIII,  B.  Place  in  a  temperature  of  36°  C.  and 
examine  at  intervals  of  10  minutes.  Describe  the  changes 
you  observe.  Test  the  final  product  with  biuret  reagent. 
Is  it  protein?^Boil  it.  Does  it  coagulate?  State  in  your 
own  words  what  the  gastric  juice  has  done  to  the  white  of 
egg. 

B.    Conditions  affecting  Gastric  Digestion.    Label  seven  test 
tubes,  — Tube  1,  Tube  2,  etc.,  —  and  prepare  them  as  follows: 
In  the  first  tube  place  5  c.c.  of  the  glycerine  solution  or  v%r 
dissolved  pepsin  and  dilute  with  10'  c.c.  of   water*;-    In  the 
second  put  15  c.c.  of  the  0.2%  hydrochloric  acid.     In  the    3  i 
third,  fourth,  and  fifth  tubes  place  15  c.c.  of  glycerine  solu- 
tion which  has  been  diluted  previously  with  ten  parts  of  0.2  % 
hydrochloric  acid  to  one  of  glycerine  solution.     Prepare  the 
sixth  tube  in  the  same  way  as  the  third  and  then  add  5  c.c.     _ 
of  concentrated  hydrochloric  acid.     Prepare  the  seventh  tube 

' 


PRINCIPLES    OF    DIGESTION 

in  the  same  way  as  the  third  and  then  add  5  c.c.  of  caustic 
soda  solution.  Add  to  each  of  the  seven  tubes  some  minced 
white  of  egg,  and  shake  it.  Place  Tubes  1,  2,  3,  6,  and  7  in 
a  temperature  of  36°  C.  and  keep  at  this  temperature 
for  twenty-four  hours.  Place  Tube  4  in  ice.  Boil  the  con- 
tents of  Tube  5,  cool  it  and  then  keep  it  at  36°  C.  for 
24  hours. 

At  the  end  of  twenty-four  hours  describe  the  appearance —  ^ 
of  all.  the  tubes.     Does  pepsin  alone  digest  protein?     What 
does  0.2  %  hydrochloric   acid  alone  do  to  protein?     Why      .  ..> 
are  both  present  in  the  stomach?     What  effect  does  cold 
have  on  gastric  digestion?     Why  is  much  ice  water  bad  for 
digestion?     What  does  boiling  do  to  gastric  juice?     What  is    O~" 
the  effect  of  strong  acid?     strong  base?     Why  is  sodium 
bicarbonate  given  in  cases  of  sour  stomach?     Can  saliva  act     \tul 
on  starch  in  the  stomach?  1     Reason?  ~fe  •v^Z^-    c^v\ 

C.  Effect  of  Gastric  Juice  on  Other  Nutrients.    Prepare  three 
tubes  and  add  to  each  10  c.c.  of  artificial  gastric  juice.     To 
tube  1  add  a  piece  of  white  of  egg  (control).     To  tube  2  add 
a  piece  of  beef  fat.     To  tube  3  add  a  little  starch.     Place  at 
36°  C.  for  24  hours.     At  the  end  of  that  time  examine.     Does 
gastric  juice  digest  fat?  starch? 

D.  Effect  of  Gastric  Juice  on  Milk.     To  10  c.c.  of  milk 
in  a  test  tube  add  an  equal  volume  of  artificial  gastric  juice. 
What  happens  to  the  milk?^"  "Remove  some  of  the  solid 
particles  and  test  with  Millon's  reagent.     Are  they  protein?  j 
Let  stand  24  hours  at   36°  C.      Do   the  particles  digest? 
Why  is  milk  a  good  food?     Save  some  of  the  particles  for 
Ex.  XLI. 

1  Owing  to  the  slow  mixing  of  the  gastric  juice  with  food  in  the 
stomach  salivary  digestion  may  continue  there  from  20  minutes  to  40 
minutes  after  the  food  is  swallowed. 

CALIFORNIA   COLLEGE 
of  PHARMACY 


68  EXPERIMENTAL   PHYSIOLOGY 

XLI.  —  PANCREATIC  DIGESTION 

Apparatus.  —  Alcohol  extract  pancreas  or  solution  of  pancreatin, 
0.5  %  sodium  carbonate  solution,  minced  white  of  egg,  biuret  re- 
agent, starch  paste,  milk,  blue  litmus  solution,  0.2  %  HC1,  KOH 
solution,  concentrated  HC1,  test  tubes,  constant-temperature  appa- 
ratus. 

Directions.  —  A.  Action  of  Pancreatic  Juice  on  Protein. 
To  a  piece  of  minced  white  of  egg  in  a  test  tube  add  10  c.c. 
artificial  pancreatic  juice  (1  volume  alcoholic  extract  +  2  vol- 
umes 0.5  sodium  carbonate  solution,  see  Ex.  XXXVIII). 
Place  in  a  temperature  of  36°  C.  and  examine  at  intervals  of 
10  minutes.  Describe  the  changes  you  observe  and  compare 
with, the  effects  noted  in  Ex.  XL,  A.  Does  the  white  of  egg 

•ellx  Test  the  final  product  with  the  biuret  reagent :v  Is 
it  protein^  Repeat  the  above  experiment,  using  the  particles 
of  milk  curd  obtained  in  Ex.  XL,  D.  Do  they  digest? 

B.  Action   of   Pancreatic   Juice  in   Starch.     To   a   little 
starch  paste  in  a  test  tube  add  10  c.c.  artificial  pancreatic 
juice.     Place  in  a  temperature  of  36°  C.  and  test  portions 
with  Benedict's  or   Fehling's  solution  at  intervals   of    10 
minutes.     Describe    the    results.      Does    pancreatic    juice 
digest  starch?  J^sssar  flA  , 

C.  Action  of  Pancreatic  Juice  on  Fat.     To  about  20  c.c. 
of  milk  add  sufficient  blue  litmus  solution  to  impart  a  deep 
blue  color  to  the  milk.     Divide  the  milk  into  two  equal  por- 
tions and  transfer  these  to  test  tubes.     To  one  half   add 

c.c.  of  boiled  pancreatic  juice  (control)  and  to  the  other 
add  5  c.c  unboiled  pancreatic  juice.  Shake  each  mixture 
thoroughly  and  keep  at  36°  C.  for  a  laboratory  period.  At 
the  end  of  the  time  describe  any  changes  that  you  observe. 
What  does  pancreatic  juice  do  to  milk  fat?  Cw^jhl/cL/ 


PRINCIPLES   OF   DIGESTION  69 

D.  Conditions  Affecting  Pancreatic  Digestion.1  Prepare 
seven  test  tubes  and  into  each  pour  3  c.c.  of  alcoholic  ex- 
tract pancreas  and  2  c.c.  of  water.  To  these  solutions  add 
successively  (a)  5  c.c.  H20;  (6)  5  c.c.  0.2  %  HC1;  (c),  (d),  (e) 
5  c.c.  0.5  %  Na2C03;  (/)  5  c.c.  concentrated  KOH  solution; 
(g)  5  c.c.  concentrated  HC1.  Drop  into  each  a  piece  of 
minced  white  of  egg.  Place  tubes  (a),  (6),  (c),  (/),  and  (g) 
in  a  temperature  of  36°  C.  Pack  tube  (4)  in  ice.  Boil  the 
contents  of  tube  (e)  and  then  place  at  36°  C.  Tabulate  the 
results  at  the  end  of  an  hour.  Write  a  statement  giving 
the  conditions  favorable  and  unfavorable  to  pancreatic  diges- 
tion based  upon  your  results. 


XLIL  —  STUDY  OF  DIGESTIVE  ACTION  OF  BILE 


Apparatus.  —  Ox  bile,  milk,  test  tubes,  pancreatic  juice,  blue 
litmus  solution,  constant-temperature  apparatus. 

Directions.  —  Prepare  four  test  tubes  as  follows:  Into  each 
put  10  c.c.  fresh  milk.  Add  to  tube  1,  10  c.c.  of  water. 
To  tube  2  add  5  c.c.  of  bile  and  5  c.c.  of  water.  To  tube  3 
add  5  c.c.  of  bile  and  5  c.c.  pancreatic  juice.  To  tube  4 
add  5  c.c.  pancreatic  juice  and  5  c.c.  water.  Shake  well  and 
place  the  four  tubes  at  36°  C.  after  coloring  each  blue  with 
the  litmus  solution.  Let  stand  and  note  results.  Does  bile 
alone  digest  milk  fat?  Does  bile  hinder  or  help  the  pan- 
creatic digestion  of  milk  fat? 

Let  tubes  1  and  2  stand  for  several  days.  Does  bile 
prevent  the  putrefaction  of  milk? 

State  your  conclusions  as  to  the  digestive  power  of  bile 
as  observed  in  the  above  results. 

1  This  experiment  may  be  repeated  with  starch  paste  or  protein  if 
desired,  using  the  same  method  described  for  milk. 


70 


EXPERIMENTAL  PHYSIOLOGY 


XLIIL  —  MICROSCOPIC  ANATOMY  OF  THE  DIGESTIVE 
TRACT  (OPTIONAL) 

Apparatus.  —  Prepared  slides  of  the  cross  sections  of  the  walls 
of  the  esophagus  (middle  part),  stomach  (pyloric  section),  small 
intestine  (injected  blood  vessels);  compound  microscope. 

Directions.  —  Make  drawings  of  each  section  studied  and 
label  the  parts.  See  Figs.  30  and  31. 


nun. 


FIG.  30.  —  Vertical  Section 
of  the  Coats  of  the 
Stomach;  d,  surface  of 
mucous  membrane,  and 
mouths  of  gastric  folli- 
cles; ra,  gastric  tubuli, 
or  follicles;  mm,  dense, 
connective  tissue ;  sra, 
sub-mucous  tissue;  cm, 
transverse  muscular  fi- 
bers; Im,  longitudinal 
muscular  fibers;  s,  fi- 
brous, or  serous,  coat. 


FIG.  31. — Section  of  Injected  Small  Intestine 
of  Cat:  a,  6,  mucosa:  g,  villi;  t,  their  absorb- 
ent vessels;  h,  simple  follicles;  c,  muscularis 
mucosse;  d,  sub-mucosa;  e,  e,  circular  and 
longitudinal  layers  of  muscle;  /,  fibrous  coat. 
All  the  dark  lines  represent  blood  vessels 
filled  with  an  injection  mass. 


PRINCIPLES   OF  DIGESTION 


71 


XLIV.  —  TABULATION  OF  NUTRIENT  DIGESTION 
(OPTIONAL) 

Directions.  —  Fill  out  the  following  table  from  the  results 
obtained  in  the  preceding  exercises.  If  a  given  nutrient 
is  digested  by  more  than  one  reagent,  indicate  it  by  sepa- 
rate entries  for  each  in  the  table. 


NUTRIENT 

REGION  OF  ALIMENTARY 
TRACT  DIGESTED  IN 

DIGESTIVE  REAGENT 

NAME    OF   DIGESTED 
PRODUCT 

Protein 

Protein 

Starch 

Starch 

Fats 

Fats 

BLOOD 

_/ 

XLV.  —  GENERAL  PROPERTIES  OF  BLOOD 

Apparatus.  —  Glass  slides  and  cover  glasses,  magnifier,  microscope, 
needle,  physiological  salt  solution  (0.6  %  solution),  neutral  carmi- 
nate  of  ammonia. 

Directions.  —  Wind  a  handkerchief  tightly  around  the 
thumb,  just  below  the  joint.  Now  bend  the  upper  joint. 
The  blood  will  collect  on  the  top  of  the  thumb  just  below 
the  nail.  Sterilize  a  needle  by  holding  it  a  second  in  a  flame, 
and  prick  the  thumb  just  below  the  nail.  The  blood  from 
the  puncture  may  be  easily  and  quickly  transferred  to  a 
glass  slide. 

A.  With  a  magnifier  examine  a  drop  mounted  as  above. 
Is  it  all  liquid?     Is  it  the  same  color  throughout?     Describe 
the  color  at  the  edge  of  the  drop.     Let  the  drop  remain  on 
the  slide  for  ten  minutes  and  examine  again.     Is  it  liquid 
now?     Prick  at  it  with  the  needle  point  and  describe  its 
consistency.     This  formation  is  called  a  dot.     Examine  the 
puncture  on  the  thumb  with  the  magnifier.     Has  it  stopped 
bleeding?     What  is  the  condition  of  the  blood  on  the  surface 
of  the  puncture?     Does  it  resemble  the  condition  of  the  drop 
on  the  slide?     Bind  up  the  thumb  as  before  and  flex  the 
upper  joint.     Does  the  puncture  bleed  again?     Wash  off 
the  clot  with  water.     Does  the  bleeding  begin  again  now? 
What  is  the  advantage  of  this  clotting  action  of  the  blood? 

B.  Mount   a   drop   of  blood    quickly,    and    examine    at 
once  with  the  high  power  of  the  microscope.     Note  the 
rouleaux  of  colored  corpuscles.     What  is  their  color?     Note 

72 


BLOOD 


73 


also  the  white  or  colorless  corpuscles  (colorless  corpuscles 
tend  to  stick  to  glass;  hence  they  will  remain  if  the  cover 
glass  is  pressed  with  a  needle  so  that  the  current  will  drive 
the  others  aside,  and  they  can  then  be  more  readily  seen). 
What  is  the  color  of  the  liquid  in  which  the  corpuscles  are 
floating?  This  liquid  is  called  the  plasma.  Let  this  prepa- 
ration stand  for  fifteen  minutes  and  then  run  under  the 
cover  glass  a  drop  of  strong  solution  of  neutral  carminate 
of  ammonia.1  This  decolorizes  the  red  corpuscles  but  brings 


FIG.  32.  —  Blood  Corpuscles:  A,  red  corpuscles  in  rouleaux;  a,  a,  colorless  corpuscles 
(X  400);  B,  red  corpuscles  in  focus;  C,  view  of  edge;  D,  three-quarters  view;  E, 
red  corpuscle  swollen  with  water;  F,  G,  H,  distorted  red  corpuscles. 

out  the  nuclei  of  the  white  corpuscles  and  the  fibrin  fila- 
ments. Draw  some  of  the  white  corpuscles  and  note  the 
shape  of  the  fibrin  filaments.  Note  how  the  entanglement 
of  these  filaments  forms  the  foundation  of  the  clot. 

C.  Mount  a  drop  of  blood  as  in  B,  but  before  covering  it 
with  the  cover  glass,  add  a  drop  of  physiological  salt  solu- 
tion. This  causes  the  separation  of  the  red  corpuscles. 
Draw  a  surface  view  and  an  edge  view  of  a  red  corpuscle 
under  the  high  power.  How  do  the  red  corpuscles  differ 
in  appearance  from  the  white  corpuscles?  Have  they  a 
nucleus? 

1  A  permanent  mount  may  be  made  of  this  preparation  if  a  little  glycer- 
ine is  allowed  to  diffuse  under  the  cover  glass  and  the  cover  slip  is  then 
cemented  to  the  glass  with  gold  size. 


74  EXPERIMENTAL   PHYSIOLOGY 

XLVI.  —  STUDY  OF  Ox  OR  HOG  BLOOD 

Apparatus.  —  Five-ounce  bottles,  fresh  blood,  egg  beater,  test 
tubes,  food-testing  materials,  constant-temperature  apparatus,  com- 
pound microscope,  slides  and  cover  glasses,  distilled  water,  dialyzer. 

Directions.  —  Obtain  from  a  butcher  a  quart  or  more  of 
fresh-drawn  blood.  Divide  this  among  the  five-ounce  bottles 
as  follows : 

Bottle  1.  Fill  with  fresh  blood  and  cork  so  as  to  exclude 
all  air. 

Bottle  2.     Fill  two-thirds  full  and  leave  uncorked. 

Bottles  3,  4,  and  5.     Fill  two-thirds  full  and  cork. 

Place  the  remainder  of  the  blood  in  a  basin  and  whip 
vigorously  with  an  egg  beater  or  twigs.  Take  off  the  stringy 
substance  that  collects  on  the  beater,  and  wash  it  in  water 
until  it  has  lost  its  red  color.  Put  it  in  Bottle  6  and  add 
to  it  a  little  water. 

Pour  the  whipped  blood  into  a  suitable-sized  bottle  and 
label  it  "  Bottle  7."  Leave  uncorked. 

A.  Study  of  Coagulation  or  Clotting.  Place  Bottles  1  and 
2  in  ordinary  room  temperature.  Examine  frequently  for 
several  days.  In  which  bottle  does  the  clot  form  quickest? 
Does  the  absence  of  air  in  Bottle  1  have  any  effect  on  the 
rate  of  clotting? 

Place  Bottle  3  in  a  constant  temperature  of  36°  C.  and 
pack  Bottle  4  in  ice.  In  which  does  the  clot  form  quickest? 
Does  temperature  affect  the  rate  of  clotting? 

Place  Bottle  5  under  the  same  conditions  as  1  and  2  but 
shake  from  time  to  time.  Does  this  affect  the  rate  of 
clotting? 

Place  Bottle  7  with  1,  2,  and  5.  Examine  after  three  days. 
Has  this  blood  clotted?  What  is  missing  in  it?  (The  sub- 
stance is  called  fibrin.) 


BLOOD  75 

Summarize  the  conditions  best  suited  to  clotting. 

B.  Study  of  the  Clot.     Pour  off  the  liquid  from  all  the 
bottles  in  which  a  clot  has  formed  and  place  it  in  Bottle  8. 
(This  liquid  is  called  serum.)     Then  break  one  of  the  bottles 
containing  a  clot  and  remove  the  clot  entire.     What  is  its 
shape?  color?  consistency?     Cut  off  a  thin  slice  of  it  and 
examine  it   under  the  microscope.     What   parts   can  you 
distinguish?     Does  it  contain  any  corpuscles?     The  jelly- 
like  substance  is  to  be  found  in  its  pure  state  in  Bottle  6. 
Examine  some  of  this  fibrin.     What  is  its  color?     Test  it 
for  protein.     What  is  the  result?     Explain  in  a  few  words 
the  formation  of  a  clot  and  the  part  played  in  its  formation 
by  the  fibrin  and  the  corpuscles. 

C.  Study  of  the  Serum.     Examine  the  liquid  in  Bottle  8. 
What  is  its  color?     Why  is  it  not  red? 

Test  a  little  with  iodine  solution  for  starch.  Since  starch 
must  be  digested  before  it  can  be  absorbed  into  blood,  why 
should  you  expect  this  result? 

Test  some  of  the  serum  with  Benedict's  or  Fehling's 
solution  for  the  presence  of  grape  sugar.  Do  you  get  a 
strong  test?  What  does  this  result  suggest  as  to  the  amount 
present? 

Burn  a  little  serum  on  a  piece  of  platinum  foil.  Does  it 
contain  any  mineral  matter? 

Place  a  drop  on  a  piece  of  unglazed  paper  and  let  it  evap- 
orate. Does  it  leave  a  grease  spot? 

Heat  a  little  serum  and  test  for  proteid.  Can  fibrin  be 
present?  Explain  the  result  of  the  test.  What  use  is  made 
of  the  nutrients  present  in  serum?  How  do  they  get  into 
the  serum?  What  function  of  the  blood  does  the  presence 
of  these  nutrients  suggest? 

D.  Study  of  Defibrinated   Blood.     Examine  the  contents 


76  EXPERIMENTAL  PHYSIOLOGY 

of  Bottle  7.  How  does  this  blood  differ  from  fresh  blood? 
from  serum? 

Place  some  of  this  blood  in  the  dialyzer.  Fill  the  outer 
jar  with  distilled  water.  Does  the  color  of  the  water  in  the 
outer  jar  change?  After  a  time  test  the  water  in  the  outer 
jar  for  protein,  grape  sugar,  minerals.  What  part  of  the 
blood  osmoses? 

Fill  a  bottle  half  full  of  defibrinated  blood  and  shake  it 
vigorously.  Does  it  change  in  color?  What  was  mixed 
with  the  blood  by  shaking  the  bottle? 

XL VII.  —  CRYSTALLIZATION  OF  HAEMOGLOBIN  FROM 
BLOOD  (OPTIONAL) 

Apparatus.  —  Defibrinated  blood,  microscope  slide,  cover  glass, 
compound  microscope. 

Directions.  —  To  one  drop  of  defibrinated  blood  on  a 
slide  add  one  drop  of  water.  Mix  the  two  drops  thoroughly, 
but  use  care  not  to  spread  them..  Allow  the  mixed  drops 
to  dry  in  the  air  until  a  comparatively  wide  dry  border  is 
formed.  Cover  with  cover  glass  and  look  for  crystals  of 
haemoglobin  with  the  compound  microscope. 

XLVIIL  —  DETECTION  OF  BLOOD  IN  BLOOD  STAINS 

(OPTIONAL) 

Apparatus.  —  Blood-stained  cloth,  evaporating  dish,  compound 
microscope  slides  and  cover  glasses,  solid  sodium  chloride,  lamp, 
glacial  acetic  acid. 

Directions.  —  A.  Spread  the  cloth  in  an  evaporating 
dish  and  moisten  thoroughly  with  water.  Squeeze  the 
water  out  into  the  dish.  Then  examine  a  drop  of  this  liquid 
with  the  microscope  for  blood  corpuscles. 

B.  Hcemin  Test  (Teichman's).     Place  a  drop  of  the  cloth 


BLOOD  77 

extract  on  a  microscope  slide.  On  a  second  slide  place  a 
drop  of  blood  obtained  as  described  in  Ex.  XLV  (control). 
To  each  drop  add  a  minute  grain  of  sodium  chloride  and 
carefully  evaporate  to  dryness  over  a  low  flame.  Put  a 
cover  glass  in  place,  and  run  under  it  a  drop  of  glacial  acetic 
acid.  Warm  gently  until  gas  bubbles  form.  Add  now 
another  drop  of  the  acetic  acid,  cool  the  preparation,  ex- 
amine under  the  microscope,  and  describe  the  crystals 
(haemin  crystals)  which"  form.  Would  this  be  an  absolute 
test  for  blood?  for  human  blood? 


CIRCULATION  AND  THE  BLOOD   SYSTEM 


XLIX. — PROPERTIES  AND  LOCATION  OF  ARTERIES  AND 

VEINS 

Apparatus. —  A  watch  with  a  second  hand,  a  needle,  a  chemical 
thermometer. 

Directions.  —  Examine  the  back  of  the  hand  and  wrist 
and  locate  the  dark-colored  veins.  Is  the  blood  this  color? 
Place  your  finger  on  a  vein.  Can  you  feel  any  motion?  Is 
there  any  difference  in  the  size  and  prominence  of  the  veins 
when  you  exercise  violently?  Why  should  you  expect  this 
result? 

Find  your  pulse  on  the  palm  side  of  the  wrist.  Count  its 
beats  and  record  the  number  per  minute.  Test  this  rate  at 
various  times  of  the  day.  Is  it  uniform  at  all  times?  Test 
your  body  temperature  at  the  same  time  by  placing  the  bulb 
of  the  chemical  thermometer  under  the  tongue.  Does  the 
temperature  vary  with  the  pulse  rate?  Does  either  increase 
after  violent  exercise?  If  food  is  burned  up  by  exercise,  and 
blood  contains  oxygen  and  food,  how  do  you  account  for 
these  effects? 

Examine  other  parts  of  the  body  for  veins  and  arteries 
(pulse  always  indicates  the  presence  of  an  artery).  Which 
are  most  numerous  on  the  surface?  Which  are  best  pro- 
tected? The  bleeding  of  a  cut  artery  is  much  more  difficult 
to  stop  than  that  of  a  vein,  owing  to  its  pulsation. 

Examine  the  skin  on  the  back  of  the  hand  between  two 
veins.  Can  you  see  any  blood  vessels?  Place  the  finger 

78 


CIRCULATION    AND    THE    BLOOD    SYSTEM 


79 


on  this  part.  Can  you  feel  any  pulse?  Prick  through  the 
skin  at  this  point  with  a  sterilized  needle.  Does  the  punc- 
ture bleed  by  spurts  or  steadily?  The  small  blood  vessels 
filling  these  places  are  called  capillaries  on  account  of  their 
small  size  (capillus  =  a  hair).  They  connect  the  veins  and 
arteries. 

L.  —  CIRCULATION  IN  A  FROG'S  FOOT 

Apparatus. —  Compound  microscope,  cover  slip,  live  frog,  shingle, 
wet  absorbent  cotton,  and  cloth. 

Directions.  —  Bind  a  live  frog  in  wet  absorbent  cotton, 
leaving  one  leg  extended.     Fasten  the  frog,  so  bound  in  place, 


Fia,  33.  —  Capillary  Circulation  in  the  Web  of  a  Frog's  Foot,  X  100:  a,  b,  small 
veins;  d,  capillaries  in  which  the  corpuscles  are  seen  to  follow  one  another  in  single 
series;  c,  pigment  cells  in  the  skin. 


80  EXPERIMENTAL   PHYSIOLOGY 

on  a  frog  board  (a  piece  of  shingle  with  a  hole  the  size  of  a 
cover  slip  at  one  end).  Stretch  the  web  of  the  foot  over  the 
hole  in  the  board.  Fasten  it  securely,  with  the  stretched 
web  as  level  as  possible.  Mount  this  board  on  the  micro- 
scope stage  in  such  a  way  as  to  bring  the  web-covered  hole 
under  the  objective  of  the  microscope.  With  a  pipette 
place  a  drop  of  water  on  the  top  of  the  web,  and  cover  with 
a  piece  of  cover  slip.  Illuminate  in  the  usual  way  and  focus 
first  with  the  low  and  then  with  the  high  power. 

Note  the  network  of  blood  vessels  and  the  slow-moving 
stream  of  corpuscles  within  them.  Are  the  corpuscles  the 
same  size  and  shape  as  those  in  the  human  blood?  Is 
there  only  one  kind?  Observe  that  in  some  of  the  blood 
vessels  the  blood  moves  in  spurts  at  regular  intervals.  What 
kind  of  vessels  are  these?  Does  the  blood  in  these  flow  from 
or  toward  the  body?  Follow  the  course  of  the  blood  from 
these  into  the  smaller  tubes  where  the  corpuscles  move  in 
almost  single  file.  Do  these  show  pulsations?  Trace  the 
flow  from  these  into  larger  vessels  where  no  pulsation  is 
evident.  Note  the  direction  of  flow  in  these  tubes.  What 
is  the  name  of  these  tubes?  Define  artery,  vein,  and  capillary 
in  terms  of  the  direction  of  blood  flow. 


LI 


.  —  MINUTE   STRUCTURE   OF  ARTERIES  AND  VEINS 
(OPTIONAL) 


Apparatus.  —  Prepared  slides  of  cross  sections  of  arteries  and 
veins,  compound  microscope. 

Directions.  —  Note  that  both  artery  and  vein  have  three 
coats:  a  lining  of  epithelial  cells  called  here  endothelium,  a 
middle  layer  consisting  of  a  mixture  of  muscle  and  elastic 
fibers,  and  the  outside  layer  or  coat  of  connective  tissue 


CIRCULATION   AND   THE    BLOOD   SYSTEM  81 

bundles.  Make  careful  drawings  of  the  two  preparations, 
showing  the  location  and  form  of  these  layers,  and  label 
the  above-mentioned  parts. 
In  which  of  the  two 
forms  of  blood  vessels  is 
the  elastic  and  muscular 
coat  thickest?  Why 
should  you  expect  this 
condition  from  the  method 

of  flow  of 'blood  in  each?    IM^feag^MW-d 
What    is    the    special    ad- 
vantage of  the    elastic  fi- 
bers   in    the    artery?      In 

What    Way    do    they    aid    tO    FIG.   34.  —  Cross    Section    of   an   Artery:    a, 
l  ±U  ~^11^,.:~~     -Gll^         endothelium;    6,    muscular    layer;    c,     con- 

keep  the   capillaries  filled      nective  tiggue;  df  small  artery  to  nourish 

at   the  end   of    an  artery      large  one. 

pulsation?     Is  the  pressure  greatest  in  arteries  or  in  veins? 


LIL  —  STRUCTURE  OF  THE  HEART 

Apparatus.  —  Sheep's  heart  from  the  butcher  with  pericardium 
attached,  bristle  seekers,  dissecting  instruments. 

Directions.  —  Locate  the  parts  named  below,  and  make 
drawings  to  show  their  position. 

A.  Note  that  the  heart  moves  easily  inside  a  loose  sac. 
Cut  this  pericardium  open  and  observe  its  slippery  inner 
coat.     Note  a  similar  coat  on  tiie  outside   of  the  heart. 
What  lies  between  these  two  coat$?<   This  liquid  and  the 
slippery  coats  prevent  friction  when  the  heart  pulses. 

B.  Carefully  cut  away  the  pericardium  from  the  blood 
vessels,  and  the  fat  from  the  surface  of  the  heart.     Locate 
the  aorta,  vence  cavce,  pulmonary  veins  and  artery,  and  push 
bristle  seekers  through  these  blood  vessels  into  the  heart. 


82 


EXPERIMENTAL   PHYSIOLOGY 


C.   Examine  the  outside  of  the  heart  and  locate  the  follow- 
ing parts  of  the  heart  proper :  right  and  left  auricles,  right  and 


ZFC, 


Fia.  35.  —  Heart  in  position  with  pericardium  removed  (Human):  TV,  trachea; 
L,  lungs;  RA,  LA,  right  and  left  auricles;  RV,  LV,  right  and  left  ventricles;  Ao, 
aorta  (two  branches);  SVC,  JVC,  superior  and  inferior  venae  cavae;  PA,  pulmonary 
artery. 

left  ventricles.  By  right  and  left  are  meant  the  parts  of  the 
heart  that  are  right  and  left  in  regard  to  the  position  of  the 
heart  in  the  body.  Which  parts  have  the  thickest  walls? 


CIRCULATION  AND  THE  BLOOD  SYSTEM 


83 


The  walls  are  made  of  muscle,  and  these  thick-walled  parts 
do  the  pumping. 

D.   Cut  off  carefully  the  front  walls  of  the  right  auricle 
and  ventricle.     By  means  of  the  bristles  locate  the  entrance 


FIG.  36.  —  Right  Auricle  and  Ventricle  (Sheep):  RA,  RV,  right  auricle  and  ven- 
tricle; IVC,  SVC,  inferior  and  superior  venae  cavse;  a,  b,  bristle  seekers  showing 
connections  between  auricle  and  ventricle,  auricle  and  vena  cava;  PA,  pulmonary 
artery;  to,  tricuspid  valve;  pp,  papillary  muscle;  sv,  semilunar  valves. 

into  the  auricle  of  the  inferior  and  superior  vence  cavce,  and 
the  entrance  into  the  ventricle  of  the  pulmonary  artery. 
Find  the  connection  between  the  auricle  and  the  ventricle 
and  note  the  tricuspid  valve  that  closes  this  entrance.  Lo- 
cate also  the  chordae  tendince  that  attach  this  valve  to  the  pap- 
illary muscles  on  the  surface  of  the  heart.  What  is  the  effect 


84 


EXPERIMENTAL   PHYSIOLOGY 


of  the  contraction  of  the  ventricle  on  the  action  of  this 
valve?     Note  finally  the  semilunar  valves  at  the  entrance  to 


Ao 


FIG.  37, —  Left  Auricle  and  Ventricle  (Sheep);  a,  6,  c,  Bristle  seekers  showing  con- 
nections of  auricle  with  ventricle,  of  auricle  with  veins,  and  of  ventricle  with  arteries; 
PV,  pulmonary  veins;  pp,  papillary  muscles;  mv,  mitral  valve;  PA,  pulmonary  ar- 
tery; Ao,  aorta;  SVC,  superior  vena  cava. 

the  pulmonary  artery.     How  does  their  arrangement  pre- 
vent the  backward  flow  of  blood  into  the  heart? 

E.  Cut  off  the  front  walls  of  the  left  auricle  and  ventricle 
in  the  same  way.  Have  they  any  connection  with  the  right 
side  of  the  heart?  Locate,  with  the  aid  of  the  bristles,  the 


of  PHARM 

CIRCULATION   AND   THE   BLOOD   SYSTEM  85 

entrance  of  the  pulmonary  veins.  How  many  enter  the 
auricle?  Find  the  entrance  from  the  auricle  to  the  ventricle, 
and  the  mitral  valve  which  guards  this  entrance.  Does  it 
show  chordae  tendinse  and  papillary  muscle  attachments? 
How  does  it  differ  in  shape  from  the  tricuspid?  Locate  the 
semilunar  valves  at  the  entrance  of  the  aorta. 

Make  a  careful  diagram  of  the  course  of  circulation  through 
the  heart  to  the  lungs  and  back  to  the  heart  and  body. 


THE  BODY  SKELETON 


LIIL  —  STUDY  OF  THE  SKELETON 

Apparatus.  —  Human  skeleton. 

Directions.  —  Tabulate  as  follows  the  various  classes  of 
bones : 


KIND  OP  BONE 

No. 

NAME  OF  BONE 

LOCATION  IN  BODY 

FUNCTION 

\\ 

LIV.  —  GROSS  STRUCTURE  OF  BONES 

Apparatus.  —  Fresh  rib,  thigh  bone,  and  dorsal  vertebra;  saw, 
needle. 

Directions.  —  A.  The  Rib,  a  flat  bone.  Draw  the  bone 
from  the  flat  side.  What  is  found  at  the  ends  of  the  bone? 
What  is  the  color,  consistency,  and  function  of  this  sub- 
stance? Bend  the  bone.  Is  it  flexible?  Pick  off  the  mem- 
brane (periosteum)  that  covers  the  bone.  Does  it  separate 
easily  from  the  bone?  Does  it  tear  easily?  Are  all  parts 
of  the  bone  protected  by  this  covering? 

Saw  the  rib  across.  Examine  the  section  and  draw  it, 
labeling  the  parts  in  the  order  in  which  they  occur.  What 
part  is  periosteum?  hard  bone?  spongy  bone?  marrow? 
Examine  the  central  marrow.  What  is  its  color?  How 

86 


THE   BODY   SKELETON 


87 


does  it  feel?     Heat  some  in  water  in  a  tube.     What  collects 

on  the  top  of  the  water? 

^  B.    The   Thigh  Bone,  or  Shank,  a  long 

i^*\  bone.  Draw  the  bone,  and  shade  with 
different  colors  the  parts  that  are  covered 
with  cartilage  and  with  periosteum.  What 
is  the  function  of  the  enlarged  heads  of 
this  bone?  Of  what  advantage  is  it  that 
they  are  irregular  in  surface? 

Saw  the  bone  lengthwise,  draw,  and 
label  the  parts.  In  what  portion  of  the 
bone  is  the  marrow  most  plentiful?  Is 
the  shaft  solid?  What  is  the  advantage 
of  this  condition? 

C.  The  Dorsal  Vertebra.  Draw  a  dor- 
sal vertebra  from  the  side  and  from  the 
top.  With  the  aid  of  the  diagram  locate 
the  following  parts:  The  body  of  the 
vertebra,  spinous  process,  transverse  proc- 
esses, spinal  cavity,  rib  articulations,  ver- 


3 


Fia.  38. —  Thigh  Bone,  Fia.  39.  —  A  Dorsal  Vertebra:  1,  centrum  or  body;  2, 
in  Longitudinal  Sec-  spinous  process;  3,  spinal  cavity;  4,  transverse  process; 
tion.  5,  rib  articulation;  6,  vertebral  articulation. 

tebral  articulations.     How  are  the  articulations  protected? 
What  is  the  function  of  the  processes? 


88  EXPERIMENTAL   PHYSIOLOGY 

LV.  —  COMPOSITION  OF  BONE  (OPTIONAL) 

Apparatus.  —  Two  clean  ribs,  a  soup  bone  split  in  two,  20% 
hydrochloric  acid,  bottle  big  enough  to  hold  rib,  evaporating  dish, 
food-testing  materials,  Bunsen  burner. 

Directions.  —  A .  Place  one  of  the  ribs  in  the  bottle  and 
fill  the  bottle  with  the  20  %  hydrochloric  acid.  Let  it  stand 
for  a  few  days.  At  the  end  of  that  time  examine  it.  Has  it 
changed  in  shape?  Take  it  out  of  the  bottle  and  bend  it. 
What  power  has  it  lost?  What  substance  is  left?  Hold  a 
little  of  it  in  the  flame.  Does  it  burn?  Pour  a  little  of  the 
acid  from  the  bottle  into  the  evaporating  dish  and  evapo- 
rate to  dryness.  What  kind  of  substance  is  left?  What 
material  did  the  acid  dissolve  out  of  the  bone? 

B.  Burn  the  other  rib.     What  is  the  shape  of  the  part  that 
is  left?     Is  it  flexible?     Put  some  of  it  in  the  acid.     Does  it 
dissolve?     Name  the  two  main  constituents  of  bone. 

C.  Cover  the  split  soup  bone  with  water  and  gradually 
bring  to  a  boil.     Strain  off  the  liquid  and  let  it  cool.     What 
do  you   find  floating  on  the  surface?     What  forms  as  it 
cools?     What  is  the  character  of  this  substance?     Test  for 
nutrients. 


^ 

LVI.  —  STRUCTURE  OF  A  JOINT 
Apparatus.  —  Fresh  leg  joint  of  lamb  or  veal,  scalpel. 

Directions.  —  Examine  the  tissue  that  binds  ttie  two 
bones  together.  What  is  the  character  of  these  bands,  or 
ligaments?  Are  they  flexible?  How  do  they  control  the 
direction  of  movement  of  the  bones?  Cut  off  the  ligaments 
with  a  scalpel.  Note  the  liquid  found  within.  What  does 
it  look  like?  (It  is  a  lubricant  called  synovial  fluid.) 

Examine  the  ends  of  the  bones.     With  what  are  they 


THE    BODY   SKELETON 


89 


covered?     Press  this  surface.     Is  it  elastic?     What  is  the 
advantage  of  this?     Is  the  surface  smooth?     Of  what  ad- 


Pelvic  Bone 

Synovial  Membrane 

Head  of  Femur 

— Round  Ligament 

- f(  T\: —  Capsular  Ligament 


FIG.  40.  —  A  Joint. 


vantage  is  this?     What  is  the  reason  for  the  enlarged  ends  of 
the  bones?  for  their  irregular  surfaces? 


-f 


LVIL  —  FORMS  OF  JOINTS 

Apparatus.  —  The  human  skeleton. 

Directions.  —  Examine  the  following  joints  and  describe 
the  range  of  motion  of  each :  Knee,  elbow,  vertebral,  shoulder, 
hip,  jaw,  head,  and  spine,  bones  of  the  skull,  ribs. 

Name  the  bones  united  in  each  case  and  classify  the  joints 
under  the  following  names:  hinge,  ball  and  socket,  gliding, 
rotary,  dovetail,  symphysis. 

Which  of  the  above  are  movable  joints?  fixed? 


MUSCLES   AND    MOTION 
LVIII.  —  DISSECTION  OF  THE  MUSCLES 

Apparatus.  -  The  body  of  the  rat  used  in  Ex.  XXXVI  (any 
other  animal  will  serve  the  purpose,  and  if  a  demonstration  is  desired 
for  the  study  of  the  leg  muscles  the  leg  of  a  sheep  may  be  substi- 
tuted), scalpel. 

Directions.  —  Carefully  cut  off  the  hind  leg  of  the  rat, 
close  to  the  hip  joint,  and  remove  the  skin.  Note  the 
muscles  covering  the  bones  and  the  glistening  white  muscle 
sheath  (perimysium)  covering  each  muscle.  At  the  ends 
of  the  muscles  note  the  white  tendons.  Are  the  muscles 
attached  directly  to  the  bones?  The  end  of  the  muscle  that 
moves  most  in  contraction  is  called  its  insertion;  the  one 
that  moves  least,  its  origin.  Where  are  the  tendons  most 
numerous?  How  does  this  arrangement  avoid  clumsiness 
in  the  foot?  Compare  with- the  arrangement  in  your  own 
hand  and  foot.  Is  it  the  same? 

Separate  the  muscles  without  cutting  them,  and  pull 
on  each  to  determine  what  part  of  the  leg  it  controls. 
Muscles  that  extend  a  joint  are  called  extensors,  those  that 
bend  it  are  called  flexors.  Note  that  all  these  muscles  have 
a  thick  center,  or  belly,  and  tapering  ends  with  tendons 
attached  at  the  ends.  Those  muscles  with  two  tendons  at 
the  origin  are  called  biceps;  those  with  three,  triceps.  Ex- 
amine one  of  these  tendons.  How  is  it  different  from  a 
muscle?  Is  it  elastic?  Why  should  you  expect  this  from 
its  use? 

Remove  the  skin  from  the  sides  of  the  body.  How  do 

90 


MUSCLES   AND   MOTION  91 

the  underlying  muscles  differ  from  the  leg  muscles?  Have 
they  tendinous  ends?  What  two  classes  of  muscles  based 
upon  their  form  can  you  name  from  your  study?  Mention 
some  other  parts  of  the  body  where  the  different  kinds  of 
muscles  can  be  found. 

Preserve  the  rest  of  the  rat's  body  for  future  use. 

/  

LIX.  —  GROSS  STRUCTURE  OF  MUSCLE 

Apparatus.  —  A  bellied  muscle  from  the  rat  or  frog  (a  piece  of 
fresh  beef  will  serve),  needles,  compound  microscope  and  slides,  food- 
testing  materials. 

Directions.  —  Boil  the  muscle  in  water  for  a  few  moments 
and  pick  it  to  pieces  with  the  needles.  Note  that  it  sepa- 
rates easily  into  bundles.  Why  is  cooked  beef  more  easily 
chewed  than  raw?  Examine  the  perimysium  covering  the 
bundles.  What  sort  of  tissue  is  it?  Describe  its  appear- 
ance. What  purpose  does  it  serve?  Place  one  of  these 
bundles  in  a  drop  of  water  on  a  slide  and  with  the  needles 
tear  off  the  perimysium  and  tease  the  bundle  into  fibers. 
Examine  one  of  these  fibers  under  the  low  power  of  the 
microscope.  Note  its  covering  (sarcolemma)  and  its  striated 
appearance.  All  muscles  under  direct  nerve  control  (volun- 
tary muscles)  show  this  striation.  (For  the  minute  anatomy 
of  this  fiber  see  Ex.  XXX.) 

Apply  the  xanthoproteic  and  other  nutrient  tests  to  pieces 
of  the  muscle.  From  the  strength  of  the  various  reactions, 
what  is  the  main  constituent  of  muscle?  Why  does  an 
athlete  require  a  diet  rich  in  protein? 

LX.  —  NERVE  MUSCLE  PREPARATION  (OPTIONAL) 

Apparatus.  —  Put  a  frog  in  a  bottle  or  jar,  pour  in  a  little  chloro- 
form, and  cork  the  bottle.  As  soon  as  the  frog  is  still,  remove  it 
from  the  jar  and,  with  a  scalpel,  sever  the  spinal  cord  just  back  of 
the  skull.  With  a  wire,  destroy  the  brain  and  spinal  cord.  Dissect 


92 


EXPERIMENTAL  PHYSIOLOGY 


away  a  hind  leg;  remove  all  the  muscles  except  the  gastrocnemius, 
and  separate  this  at  its  lower  attachment.  Fasten  the  femur  strongly 
in  a  clamp.  With  a  pointed  glass  rod  separate  the  sciatic  nerve  at 
the  upper  part;  do  not  touch  it  with  metal  instruments.  Into  the 


FIG.  41.  —  sc,  sciatic  nerve;  g,  gastrocnemius;  ad,  b,  etc.,  other  muscles. 

lower  end  of  the  muscle  insert  a  hook  and  connect  it  with  a  lever  as 
in  Fig.  42.  Connect  a  copper  wire,  insulated  except  at  the  end 
which  is  to  be  used  as  an  electrode,  with  each  pole  of  a  battery  of 
two  dry  cells.  For  convenience  a  key  of  some  kind  may  be  inserted 
in  the  circuit  to  make  and  break. 

Directions.  —  Touch  the  free  end  of  the  nerve  with  the 
two  electrodes.  What  happens  to  the  muscle?  Record  the 
extent  of  the  action.  This  shows  that  nerve  stimulation  may 
cause  the  muscle  to  move.  Keeping  the  electrodes  in  con- 
tact with  the  nerve,  note  whether  the  action  continues. 


MUSCLES  AND  MOTION 


93 


Remove  the  electrodes.     What  happens?     Repeat  this  proc- 

ess several  times  and  mark  the  distance  that  the  lever  moves 

each    time.       Is    it    the 

same?     Does    the  action 

increase  or  decrease? 

This  result  illustrates 

what   may  happen  from 

overstimulation;  namely, 

muscle  fatigue. 

Repeat  the  experiment, 
applying  the  current  to 
the  body  of  the  muscle 
instead  of  the  nerve. 
Compare  with  the  results 
of  the  first  experiment  as 
to  the  extent  and  strength 
of  the  action. 

In  both  of  the  above  experiments  what  property  of  the 
muscle  is  stimulated?  Why  is  muscle  called  contractile  tissue? 


FIG.  42. —  Nerve  Muscle  Preparation:  s,  set 
screw;  c,  clamp;  /,  femur;  m,  gastrocnemius; 
n,  sciatic  nerve;  h,  hook;  /,  lever;  «,  elec- 
trodes; 6,  battery. 


LXI.  —  STUDY  OF  LEVER  ACTION  (OPTIONAL 
Apparatus.  —  Wooden  bar  with  holes  near  the  ends  and  at  the  mid- 
dle (exactly  halfway  between  the  end  holes),  spring  balances. 

Directions.  —  A.  Support  the  bar  by  the  middle  hole  (see 
Fig.  43,  A)  and  trim  the  bar  till  it  balances  level.  Fasten 
the  spring  balances  in  the  two  end  holes.  Pull  down  on 
each,  keeping  the  bar  horizontal.  Compare  the  pulls  regis- 
tered by  the  balances.  What  is  their  relation?  Attach  one 
balance  halfway  between  the  end  and  middle  holes,  keeping 
the  second  balance  in  the  other  end  hole.  Pull  until  the  bar 
is  level  as  before.  What  is  the  relation  of  the  registered 
pulls  now?  Verify  the  following  law  by  changing  the  posi- 
tion of  the  two  balances. 


94 


EXPERIMENTAL   PHYSIOLOGY 


Weight  X  perpendicular  distance  from  the  pivot  equals 
pull  X  perpendicular  distance  from  the  pivot.  (Perpendic- 
ular distance  is  measured  from  the  pivot  at  right  angles  to 
the  direction  in  which  the  force  is  acting.) 

This  arrangement  of  lever  is  called  a  lever  of  the  first  class. 

B.  Support  the  bar  by  one  end  hole,  and  at  the  extreme 
end  attach  a  weight  so  that  the  bar  will  balance  level;  then 

f       \ 


FIG.   43.  —  Forms  of  Levers:   A,  1st  class;   B,  2d  class;  C,  3d  class;   W,  weight;  F, 
fulcrum  or  pivot;  P,  pull. 

insert  the  balances  in  the  other  two  holes  (see  Fig.  43,  B). 
Pull  down  with  the  one  nearest  the  pivot  (weight),  and  up 
with  the  one  at  the  end  (pull) .  Record  the  pull  and  weight 
when  the  bar  is  level,  measure  the  distances  from  the  pivot, 
and  see  if  the  law  of  A  still  holds.  This  arrangement  is 
called  a  lever  of  the  second  class. 

C0  If  the  pull  nearest  the  pivot  be  called  the  pull  and  the 
other  the  weight,  the  arrangement  is  called  a  lever  of  the 
third  class  (see  Fig.  43,  C). 

LXIL  —  LEVEKS  OF  THE  BODY  (OPTIONAL) 

Directions.  —  A .  Locate  on  the  upper  arm  the  biceps 
muscle,  or  flexor  of  the  arm.  Where  is  it  attached  to  the 
forearm  and  how  far  (perpendicular  distance)  from  the 
elbow?  Measure  the  perpendicular  distance  from  the  elbow 


MUSCLES   AND   MOTION  95 

to  the  center  of  the  palm.  If  now  we  put  a  weight  of  ten 
pounds  in  the  palm  and  bend  the  arm,  what  class  of  levers 
is  illustrated?  How  much  force  is  required  on  the  part  of 
the  muscle  to  raise  ten  pounds'  weight?  By  selecting 
different  weights  to  lift,  determine  the  maximum  strength 
of  the  biceps  muscle.  What  muscle  is  used  in  striking  an 
outward  blow  with  the  fist?  Where  is  it  located  and  in- 
serted? Note  that  the  flexors  and  extensors  in  other  parts 
of  the  body  are  usually  arranged  in  pairs. 

B.  Examine  the  relation  of  the  muscle,  weight,  and  pivot 
in  the  following  cases,  and  tell  which  class  of  lever  each 
illustrates:  Jaw  action  in  chewing,  flexing  of  the  fingers, 
movement  of  the  legs  in  kicking,  bending  the  body,  move- 
ment of  the  foot  about  the  ankle  (see  Fig.  43). 

NOTE.  —  The  instructor  can  suggest  other  problems  of  the  above 
nature  to  make  clear  the  laws  of  lever  action. 


RESPIRATION 


LXIIL  —  DISSECTION  OF  A  RAT'S  LUNGS 

Apparatus.  —  Body  of  the  rat  used  in  Exs.  XXXVI  and  LVII, 
scalpel,  glass  tube  of  one-eighth  inch  diameter. 

Directions.  —  Remove  the  skin  from  the  surface  of  the 
ribs  and  throat.  Examine  carefully  the  muscles  between 
the  ribs  (intercostals) .  Seize  the  base  of  the  breastbone  and 
move  it  up  and  down.  Notice  the  motion  of  the  inter- 
costals during  this  process. 

Insert  the  glass  tube  in  the  top  of  the  windpipe  through 
the  throat  opening,  and  blow  gently  through  this  tube. 
Observe  the  motion  of  the  ribs  and  the  motion  of  the  muscu- 
lar diaphragm  that  forms  the  partition  between  the  abdom- 
inal and  the  thoracic  cavities.  Press  the  diaphragm  up  with 
the  finger  and  note  that  air  is  forced  out  of  the  tube. 

Now  cut  the  ribs  where  they  join  the  breastbone,  and  press 
them  back  to  expose  the  organs  of  the  cavity.  Sketch  the 
position  of  the  lungs  and  heart.  Compare  with  Fig.  35, 
page  82.  Note  the  texture  of  the  lungs'  and  observe  the 
windpipe  (trachea)  with  its  cartilage  rings.  (These  are  nec- 
essary to  prevent  collapse  of  the  tube.)  How  is  the  windpipe 
connected  with  the  lungs? 

Carefully  dissect  out  the  lungs  and  windpipe  and  float 
them  in  water.  Cut  them  at  the  entrance  of  the  windpipe 
and  trace  out  the  bronchi  and  their  branches.  How  do  these 
branches  end?  (This  large  amount  of  branching  allows  the 

96 


RESPIRATION 


97 


air  to  be  brought  in  contact  with  very  many  small  blood 
vessels,  through  the  walls  of  which  oxygen  is  absorbed  by 
the  blood.) 

LXIV.  —  MECHANICS  OF  RESPIRATION 

Apparatus.  —  A  glass  bell  jar  open  at  the  top,  a  glass  tube  with 
a  toy  balloon  firmly  bound  to  one  end,  a  stick  with  a  knob,  a  piece 
of  sheet  rubber,  a  one-holed  stopper  to  fit  top  of  bell  jar. 

Directions.  —  Pass  the  tube 
through  the  stopper  and  seal 
it  in  place  with  wax.  Insert 
the  stopper  in  the  top  of  the 
bell  jar  with  the  balloon  inside 
the  jar.  Tie  the  knob  into 
the  center  of  the  rubber  sheet 
and  fasten  the  latter  tightly 
across  the  base  of  the  bell  jar, 
leaving  the  stick  outside  to 
serve  as  a  handle.  With  this 
arrangement  the  tube  corre- 


Glass 


Handle 


Bel/Jar 
^Balloon 


~ffubber 
Diaphragm 


sponds  to  the  trachea,  the  bal-  FrQ-   44- — Apparatus   to   illustrate 

breathing  movements  and  their 
effect  upon  the  lungs.  The  rubber 
diaphragm  corresponds  to  the  dia- 
phragm in  the  body;  the  handle  to 

the  jar  to  the  thoracic  cavity. 
Now  move  the  handle  down- 


loon  to  the   lungs,  the   rubber 
sheet    to    the    diaphragm,    and 


the  tendon;  the  balloon  to  the 
lungs;  the  tube  to  the  trachea;  the 
bell  jar  to  the  walls  of  the  thorax. 
As  the  handle  is  lowered  the  air 
flows  down  the  tube  and  inflates 
the  balloon. 


ward    so    as     to     stretch     the 

diaphragm.     What   happens  to 

the    balloon?       What    causes 

this  action?     Move  the  handle  upward.     What  happens  to 

the  balloon  now?     Why?     How  does  the  diaphragm  secure 

rhythmic  inhaling  and  exhaling,  i.e.,  inflow  and  outflow  of 

air? 


98  EXPERIMENTAL    PHYSIOLOGY 

LXV.  —  STUDY  OF  EXPIRED  AIR 

Apparatus.  —  Chemical  thermometer,  lime  water,  test  tube,  glass 
tube,  large-mouthed  bottle,  pneumatic  trough. 

Directions.  —  A.  Temperature.  Breathe  on  the  bulb  of 
the  thermometer  and  determine  the  temperature  of  the  ex- 
pired air.  Place  the  bulb  under  the  tongue  and  determine 
the  body  temperature.  How  does  the  temperature  of  the 
expired  air  compare  with  that  of  the  body,  or  blood  tem- 
perature? Test  this  on  several  successive  days  and  note 
whether  the  temperature  varies  with  the  external  temperature 
or  is  constant. 

B.  Composition.  Breathe  on  a  piece  of  glass.  What  col- 
lects on  the  surface?  Does  expired  air  contain  more  or  less 
moisture  than  inspired  air? 

Fill  the  test  tube  half  full  of  limewater  and  blow  the  breath 
gently  through  it  by  means  of  the  glass  tube.  What  change 
takes  place  in  the  limewater?  What  does  this  indicate? 
(See  Ex.  VIII.) 

Fill  the  bottle  with  expired  air  by  the  method  of  Ex.  II. 
Turn  the  bottle  mouth  upward  and  introduce  a  lighted 
match  into  it.  Does  the  match  continue  to  burn?  What 
does  this  indicate?  (Air  expired  in  ordinary  breathing  has 
lost  about  one-fourth  of  the  oxygen  contained  in  the  air 
inspired.) 


EXCRETION 


LXVI.  —  STUDY  OF  A  LAMB'S  KIDNEY  (OPTIONAL) 
Apparatus. — A  fresh  lamb's  kidney  with  its  capsule  of  fat,  scalpel. 

Directions.  —  Carefully  remove  the  outer  layer  of  fat  and 
the  membranous  inner  capsule.  What  is  the  function  of 
this  material?  (A  dissection  of  the  rat  makes  a  good 
demonstration  of  the  location  of 
the  kidneys  and  their  relation  to 
ureter  and  bladder.)  Cut  the 
kidney  lengthwise  so  as  to  split 
the  ureter  where  it  emerges  from 
the  concave  side.  On  the  cut 
surface  make  out  the  pale  inner 
striated  medulla  and  its  pyramids 
of  Malpighi,  the  outer  cortex,  and 
the  intermediate  layer  between  the 
two.  Note  also  the  enlarged  upper 
end,  or  pelvis,  of  the  ureter;  the 
cavity,  or  sinus,  into  which  it 
opens;  and  the  tubes,  or  calices, 

i  .  i  . .  .  T         FIG.  45.  —  Diagram  of  a  Longitu- 

between  the  projecting  pyramids.       dinal  Section  of  a  Kidney:  flf 
Note    also    the    entrance    of    the 
renal  artery  into  the  kidney,  and 
the    renal    vein,    just    above    the 

ureter.      From  the  accompanying  Fig.  45   make   out  the 
parts  which  act  in  removing  the  waste.     (The  artery  brings 

99 


renal  arteiy;  c,  capillaries;  g, 
glomerulus;  t,  uriniferous  tubule; 
»,  renal  vein. 


100  EXPERIMENTAL   PHYSIOLOGY 

in  the  blood,  which  gives  up  its  waste  in  the  glomerulus. 
This  waste  is  collected  by  the  tubule  and  emptied  by  it  into 
the  ureter.  The  capillaries  collect  the  blood  which  has  been 
cleared  of  its  waste,  and  return  it  to  the  vein.) 

NOTE.  —  Prepared  sections  of  injected  and  stained  cortex  may  be 
shown  and  the  following  parts  demonstrated:  Malpighian  bodies, 
uriniferous  tubules,  and  capillaries. 

LXVIL  —  STUDY  OF  THE  SKIN 

Apparatus.  —  Prepared  slide  of  epidermis  (that  from  the  sole  of 
the  foot  preferred,  from  its  thickness),  a  vertical  section  of  a  hair, 
compound  microscope,  needle,  scissors. 

Directions.  —  A.  Surface  Study  of  the  Skin  Layers.  Ster- 
ilize a  needle  by  holding  it  in  a  flame  for  a  moment.  Run  it 
carefully  under  the  thin  outer  layer  of  skin  at  the  base  of 
the  thumb.  (This  layer  is  called  the  cuticle  or  epidermis.) 
Does  the  wound  cause  any  pain?  Are  there  any  nerves  in 
this  layer?  Does  the  wound  bleed?  Does  the  epidermis 
contain  any  blood  vessels?  With  the  needle  tear  off  a  little 
of  this  epidermis.  What  is  its  color?  consistency?  Where 
is  it  thickest  on  the  hand?  Why?  Where  else  on  the  body 
do  you  find  similar  thickening? 

What  is  the  color  of  the  skin  layer  (dermis)  under  this 
epidermis?  Prick  it  with  the  needle.  Is  it  sensitive? 
Does  it  contain  blood  vessels?  Examine  its  surface  and  note 
that  it  is  ridged.  A  magnifier  will  show  that  these  ridges 
are  made  up  of  a  series  of  points,  or  papillaz.  (Each  papilla 
marks  the  end  of  a  nerve  of  touch.  These  nerve  endings 
are  called  on  that  account  tactile  organs;  see  Fig.  46.)  Pick 
up  a  little  of  the  skin  between  the  fingers.  Is  it  attached 
to  the  underlying  muscles?  About  how  thick  is  it  on  the 
back  of  the  hand?  on  the  base  of  the  thumb? 


EXCRETION 


101 


B.  Microscopic  Study  of  a  Section.  Study  the  prepared 
slide,  under  the  high  power.  Note  the  layer  character  of 
the  epidermis,  the  papillae  with  their  blood  vessels,  the  coiled 
sweat  glands  and  their  ducts  (thick  sections  show  these 
best).  Sketch  and  label  all  parts  of  your  drawing  as  in 
the  diagram. 


Sweat-Duet 


Horny  layer  <j ; 
Pigment  layer 


Tactile  Organ 
Nerve — 
Mood  Vessels 


FIQ.  46.  —  Diagram  of  Skin  Section. 


Compare  the  action  of  the  sweat  glands  with  that  of 
the  tubuli  uriniferse  (uriniferous  tubules)  of  the  cortex 
of  the  kidneys.  When  do  we  perspire  most?  Why  does 
exercise  increase  the  amount?  What  is  one  function  of 
the  skin? 

C.  Study  of  Skin  Modifications,  (a)  Hairs.  Note  the 
location  of  hair  on  the  head.  What  is  its  function?  Ex- 
amine one  of  the  hairs  on  the  back  of  the  hand.  Cut  it. 


102 


EXPERIMENTAL   PHYSIOLOGY 


Is  it  sensitive?  Pull  it.  Where  is 
the  sensitive  portion  located? 
Where  is  the  seat  of  growth? 
What  part  of  the  skin  is  it  most 
like? 

Study  the  slide  showing  a  ver- 
tical section  of  a  hair  under  the 
low  power  of  the  microscope. 
Note  that  the  hair  is  imbedded  at 
the  base  in  a  skin  follicle,  and 
grows  from  a  skin  papilla  at  the 
bottom  of  this  follicle.  Note  also 
the  sebaceous  or  oil  glands  that 
serve  to  coat  the  hair  with  oil. 

(6)  Nails.  Make  a  drawing  of 
your  finger  nail,  showing  all  areas. 
What  parts  are  attached  to  the 
skin?  Why  is  the  part  under  the 
nail  called  the  "quick  "  ?  What  is 
one  function  of  the  nail?  Cut 
it.  Is  it  sensitive?  Pull  it. 
Where  is  its  sensitive  part  located? 
How  does  it  compare  with  the  hair 
in  this  respect?  Cut  a  nick  in  it 
and  examine  it  from  day  to  day. 

D°eS     !t     chane     position?         Where 


Fia.47.-Hair-foiricleinLongi- 

tudinal  Section:  h,  hair  shaft,  does  the  growth  of  the  nail   OCCUr? 
showing   its  medulla   or  core:          TI    u    i    j.  11       ji          ?          ,•  /• 

s,  sebaceous  gland;  w,  sheath       Tabulate    all     the    functions     of 

of  skin;  /.fatty  tissue.   (At  the  hairs,    nails,    and    skin    that    you 

base   of  the  hair   is  seen   the  i  i  j 

papiiia  that  forms  it.)  have  learned. 


NERVOUS  SYSTEM 


LXVIII.  —  DISSECTION  OF  SHEEP'S  BRAIN 

Apparatus.  —  Sheep's  head,  bone  forceps,  hammer,  scalpel,  needle, 
forceps,  50  %  alcohol. 

Directions.  —  A.  To  Remove  Brain  from  Skull.  Strike 
the  top  of  the  skull  with  the  hammer  so  as  to  crack  the 
bone,  but  not  to  force  it  into  the  brain,  and  then  carefully 
remove  the  pieces  with  the 
bone  forceps.  Be  careful  not 
to  injure  the  underlying  mem- 
brane (dura  mater)  which  lines 
the  skull  and  covers  the  brain. 
After  the  top  of  the  skull 
is  removed  slit  this  dura 
mater  around  the  edge,  and 
remove  it,  exposing  the  brain. 
Note  that  over  the  surface 
of  the  brain  is  another  mem- 
brane, the  pia,  mater.  Now 
carefully  lift  the  brain  from 

thp   flfifir   nf     thp    Qlrnll     Kpo-in-    FlG'  48.  — Upper  Surface  of   Brain   (Hu- 

ucuii,  begin       man).  j  2>  two  halveS)  Ol  hemispheres> 

ning    at      the     front.         Notice         of  cerebrum;   3,  3,  longitudinal  fissure. 

that  it  is  bound  by  nerves  and  portions  of  the  dura  mater. 
Cut  these  nerves,  leaving  as  long  ends  as  possible,  and  do 
not  cut  off  the  olfactory  lobes  which  are  on  the  under  side 

103 


104  EXPERIMENTAL    PHYSIOLOGY 

of  the  brain.     Place  the  brain  in  50  %  alcohol  to  harden, 
for  several  days.1 

B.  The  Coverings  of  the  Brain.     Tear  off  a  little  of  the 
dura  mater  with  the  forceps.     Does»it  tear  easily?     Are 
both   sides   of  it   smooth?     Where   are   its   blood   vessels? 
What  do  they  feed? 

Pick  up  a  little  of  the  pia  mater  (brain  cover)  with  the 
needle  point.  Is  it  thicker  or  thinner  than  the  dura  mater? 
Where  are  its  blood  vessels?  What  do  they  feed?  What 
are  the  functions  of  the  three  coverings  of  the  brain? 

C.  The  External  Parts  of  the  Brain.     Examine  the  top  of 
the  brain.     Note  the  two  convoluted  hemispheres  into  which 
the  fore  brain  (cerebrum)  is  divided  by  a  fissure  (the  longi- 
tudinal fissure).     Back  of  this  appears  the  wrinkled  surface 
of  the  hind  brain  (cerebellum).     Is  this  divided? 

Turn  the  brain  over  and  examine  the  lower  surface. 
Note  the  olfactory  lobes  on  the  front  part  of  the  hemispheres. 
What  is  their  function?  Back  of  these  locate  the  optic 
nerves,  and  note  how  they  cross  to  form  a  chiasma}  so  that 
the  right  eye  is  controlled  by  the  left  hemisphere,  and  vice 
versa.  Just  back  of  this  may  be  seen  the  pons,  or  bridge, 
that  connects  the  two  sides  of  the  cerebellum,  and,  coming 
out  in  front  of  it  on  each  side,  the  stalks  (crura  cerebri),  which 
spread  out  into  the  two  hemispheres  of  the  cerebrum.  Note 
that  the  stalks  are  the  forward  projections  of  a  conical  spinal 
bulb  which  comes  between  the  cerebellum  and  the  pons  and 
is  continued  backward  into  the  spinal  cord.  This  bulb  is  a 
part  of  the  hind  brain,  and  is  called  the  medulla.  All  along 
the  under  side  of  the  brain  are  located  the  cranial  nerves, 
occurring  in  pairs.  Beginning  at  the  front,  locate  the  pairs 
named  in  the  following  table : 

1  Preserve  the  skull,  with  eyes,  for  use  in  Ex.  LXXV. 


NERVOUS    SYSTEM 


105 


Olfactory  Bulb 

{ to  which  is  attached 
the  Olfactory  Nerve) 

Pituitary  Body — _____ 

Optic  Nerve 

Optic  Chiasma 

Oculomotor  Nerve — . 

Trochlear  Nerve 

Trigeminal  Nerve 

Pons  Varolii — 

Abducens  Nerve — 

Facial  Nerve — 

Auditory  Nerve — 

Glossopharyngeal  Nerve  — 

Vagus  Nerve — 

Spinal  accessory  Nerve — 

Hypoglossal  Nerve- - 

Medulla  Oblongata 

First  Spinal  Nerve 

Cerebellum 

Spinal  Cord 

Second  Spinal  Nerve 


FIG.  49.  —  Under  Surface  of  Brain  (Human). 


NAME 

FUNCTION 

1st  pai                 Olfactory 

Smell  —  Sensory 

2d    pai                 Optic 

Sight  —  Sensory 

3d    pai                Oculomotor 

Eye  Muscles  —  Motor 

4th  pai                 Trochlear 

Eye  Muscles  —  Motor 

5th  pai                 Trigeminal 

Facial  —  Sensory  and  Motor 

6th  pai                Abducens 

Eye  Muscles  —  Motor 

7th  pai                Facial 

Motor,  mainly 

8th  pai                 Auditory 

Hearing  —  Sensory 

9th  pai                Glossopharyngeal 
10th  pai                Vagus 

Tongue  and  Throat  —  Sensory  and  Motor 
Thorax  and  Abdomen^  —  Sensory  and   Motor 

llth  pai                 Spinal  Accessory 
12th  pair               Hypoglossal 

Motor 
Tongue  —  Motor 

D.  Vertical  Section  (right  side).  Cut  the  brain  through 
lengthwise,  parallel  to  the  line  of  the  longitudinal  fissure,  but 
one-sixteenth  of  an  inch  to  the  left  of  this  line  in  order  not 
to  cut  the  septum.  Examine  the  right  side.  Note  the 


106 


EXPERIMENTAL   PHYSIOLOGY 


white,  fibrous  body  (corpus  callosum)  which  unites  the  two 
hemispheres.  In  the  front  part  of  this  are  seen  the  thin 
membranes  (septum  lutidum)  which  inclose  between  them 


Corpus  Callosum 


Foramen  of  Monro 

Third  Ventricle 

\  Pinqal  Body 

I  Cerebrum 


Optic  Chiasma 

Pituitary  Body    /  /      / 

Oculomotor' Nerve      /      /       // 
PonsVarotii     /'       / 

Aqueduct     /      , 
Medulla  Oblongata     / 
fourth  Ventricle 


Corpora 
Quadrigemina 

Cerebellum 


Spinal  Cord 


FIG.  50.  —  Section  of  Brain. 

a  portion  actually  outside  the  brain,  but  often  called  the 
"  fifth  "  ventricle.  Below  this  is  the  fornix,  which  forms  the 
roof  of  a  true  brain  cavity  —  the  third  ventricle  —  whose 
sides  are  the  optic  thalami.  This  ventricle  projects  forward 
into  a  funnel  called  the  infundibulum.  In  the  center  of  this 
ventricle  is  a  round  body  (the  median  commissure)  which 
was  cut  through  by  the  section.  In  front  of  this  is  a  small 
aperture  (the  foramen  of  Monro)  that  connects  this  cavity 
frith  a  cavity  in  the  right  hemisphere.  The  floor  of  the  third 


NERVOUS   SYSTEM  107 

ventricle  is  formed  by  the  crura  cerebri,  which  extend  back- 
ward, between  the  pons  and  the  cerebellum,  into  the  spinal 
bulb  or  medulla,  and  this,  in  turn,  Backward  into  the  spinal 
cord.  At  the  back  of  the  third  ventricle  note  that  a  tube  or 
canal  (aqueduct)  connects  it  with  a  much  smaller  cavity  (the 
fourth  ventricle)  just  under  the  cerebellum.  Four  little  bodies 
(the  corpora  quadrigemina)  form  the  roof  of  this  tube  between 
the  fornix  and  the  cerebellum.  Note  the  treelike  internal 
structure  of  the  cerebellum.  What  causes  its  wrinkled 
surface? 

Note  the  gray  and  the  white  matter  that  make  up  the 
cerebrum.  Where  is  the  gray  matter  located?  the  white? 

NOTE.  —  The  first  ventricle  in  the  olfactory  lobes  and  the  lateral 
ventricle  may  be  shown  by  suitable  sections,  if  desired,  and  the  re- 
lation of  these  may  be  brought  out  by  the  aid  of  diagrams  of  a 
simple  brain  structure. 

LXIX.  —  DISSECTION  OF  SPINAL  COR: 

Apparatus.  —  Thin  section  of  cervical  portion  of  spinal  cord, 
glycerine,  slides,  cover  glass,  compound  microscope. 

Directions.  —  (Prepare  sections  by  placing  a  piece  of  the 
cervical  spinal  cord  for  three  or  four  weeks  in  Miiller's  fluid 
[2|  parts  of  potassium  bichromate,  1  part  of  sodium  sulphate, 
100  parts  of  water].  Then  wash  it  with  water  and  place  it 
in  30  %  alcohol  for  a  few  days.  Then  transfer  it  to  95  % 
alcohol.  Cut  a  thin  cross  section  and  mount  it  in  glycerine. 
Cover  it  with  a  cover  glass). 

Examine  under  the  low  power.  Note  the  outer  covering 
of  pia  mater.  Note  the  distribution  of  the  gray  and  white 
matter.  Sketch  it.  Is  it  the  same  as  in  the  brain?  Note 
the  division  into  two  parts  by  a  deep  anterior,  and  a  shal- 
low posterior  fissure.  Note  also  two  fissures  in  each  half  (an^ 


108 


EXPERIMENTAL   PHYSIOLOGY 


terior  and  posterior  lateral)  through  which  the  central  gray 
mass  reaches  the  surface.  The  gray  masses  in  each  half  of 
the  cord  may  be  seen  to  be  united  by  a  commissure  that 
incloses  the  central  or  neural  canal.  Note  the  cellular  char- 
acter of  the  gray  matten  The  gray  matter  that  forms  the 


FIG.  51. 

posterior  horns  forms  the  core  of  spinal  nerves  of  the  sort 
called  afferent.  The  anterior  horns  form  the  core  of  effer- 
ent nerves.  (Afferent  nerves  carry  messages  to  the  cord; 
efferent,  away  from  it.)  The  white  matter  covers  these  and 
they  unite  outside  in  a  common  spinal  nerve.  (See  Fig.  51.) 
For  structure  of  a  neuron,  see  Ex.  XXXI. 


SPECIAL  SENSES 


LXX.  —  NERVE  ACTION 

Apparatus.  —  A  stop  watch,  pencil,  paper. 

Directions.  —  Let  the  teacher  write  a  vowel  on  a  piece  of 
paper  which  he  shall  keep  covered.  Arrange  the  class  in  a 
circle.  Station  a  boy  beside  the  teacher  with  a  stop  watch. 
Proceed  as  follows:  The  teacher  shows  the  vowel  to  the 
pupil  on  his  right,  who  whispers  it  to  the  pupil  on  his  right  as 
quickly  as  possible,  and  so  on  around  the  circle  to  the  teacher 
again.  All  this  as  rapidly  as  possible.  Let  the  boy  with 
the  watch  release  the  stop  at  the  second  when  the  teacher 
exposes  the  letter  to  the  pupil  on  his  right,  and  stop  it  again 
when  the  last  pupil  repeats  the  letter  to  the  teacher. ,  Divide 
the  time  elapsed  by  the  number  of  pupils.  The  result  will 
represent  the  average  reaction  time  of  each  pupil.  Change 
the  arrangement  of  the  pupils  and  note  whether  the  time 
varies.  What  muscular  action  does  each  pupil  perform  in 
receiving  and  transmitting  the  sound?  What  sensory  nerves 
are  employed?  what  motor  nerves? 

NOTE.  —  In  order  to  bring  out  various  sensation  reactions  this  ex- 
periment may  be  varied  in  many  ways  which  will  suggest  themselves 
to  the  teacher. 

LXXI.  —  CUTANEOUS  SENSATIONS     ^\ 

Apparatus.  —  A  pair  of  metal  compasses,  toothpicks,  a  dish  of 
boiling  water,  a  dish  of  ice  water,  pen  and  ink. 

Directions.  —  One  pupil  should  operate,  while  another  acts 
as  subject.  The  subject  should  be  blindfolded. 

109 


110  EXPERIMENTAL   PHYSIOLOGY 

A.  Touch.     Sharpen  the  ends  of  the  toothpicks  and  tie 
one   to   each   arm   of   the    compass.       What   is   the   least 
distance  apart  at  which  the  two  points  may  be  held  and 
felt  as  two  points,  when  applied  to  the  tips  of  the  fingers? 
the  tip  of  the  tongue?  back  of  the  hand?  forearm?  back 
of  the  neck?     Record  the   results.     Are   all   parts  of   the 
body  equally  sensitive  to  touch?      Which  parts  are  most 
sensitive? 

B.  Temperature.     Dip  a  metal  point  of  the  compasses  in 
cold  water  and  move  it  lightly  over  the  back  of  the  hand. 
Does  it  feel  equally  cold  to  all  parts  of  the  skin?     Mark 
with  an  ink  dot  those  points  where  the  sensation  is  most 
acute.      Now  heat  the  metal  point  in  the  hot  water  and 
move  it  over  the  same  area.      Locate,  as  before,  the  spots 
where  sensation  is  most  acute.     Do  the  hot  and  cold  spots 
coincide?     What  do  you  conclude  about  the  temperature 
sensation  power  of  the  skin?      Is  it  a  general  or  a  local- 
ized sensitive  power?      Test   other  areas  of  the  body  in 
the  same  way.     Are  the  temperature  spots  equally  numer- 
ous in  all  parts?     Where  are  they  most  numerous?  least 
numerous? 

LXXIL  —  STUDY  OF  THE  TONGUE 

Directions.  —  Protrude  the  tongue  as  far  as  possible  and 
with  the  aid  of  a  mirror  examine  its  surface.  Note  the 
raised  points  (the  papillce)  on  the  surface.  Observe  that 
they  are  of  three  forms:  long  and  slender  (filiform), 
mushroom-topped  (fungiform),  and  large  and  wartlike 
(circumvallate).  Draw  an  outline  of  the  tongue  and 
locate  on  it  the  regions  where  these  different  forms  are  to 
be  found. 


SPECIAL   SENSES 

LXXIIL  —  SENSATIONS  OF  TASTE  AND  SMELL 

Apparatus.  —  Onion,  sugar,  salt,  vinegar,  dilute  ammonia,  quinine, 
vanilla  or  other  flavor. 

Directions. — A.  Location  of  Taste.  Wipe  the  tongue  and 
place  on  its  tip  a  little  dry  sugar.  Has  it  any  taste?  Let  it 
dissolve^  Has  it  any  taste  nowfllepeat,  placing  the  sugar 
at  the  back  of  the  tongue.  Is  its  sweetness  more  or  less 
prominent?  Repeat  again,  using  quinine,  vinegar,  and  salt 
successively.  Where  are  the  sensations  of  bitterness,  sour- 
ness, and  saltiness  most  prominent? 

B.  Taste  and  Odor.  Examine  the  various  substances 
named  under  "  Apparatus. "  Which  have  taste?  odor? 
Place  each  of  these  substances  on  the  tongue  of  a  pupil 
who  has  been  previously  blindfolded,  and  who  is  holding 
his  nose  tightly.  Record  the  substances  recognized  by  taste 
alone.  Repeat,  leaving  the  nose  free  but  retaining  the 
blindfold.  Record  those  substances  recognized  by  smell 
alone;  by  taste  and  smell  combined. 


LXXIV.  —  HEARING;  LAWS  OF  SOUND  (OPTIONAL) 
Apparatus.  —  Stretched  wire,  bridge  to  shorten  length. 

Directions.  —  A.  Strike  the  wire.  Do  you  get  any 
sound  ?  What  is  the  wire  doing?  All  sound  depends 
upon  vibration:  test  several  sounding  bodies  to  verify  this 
statement. 

B.  Move  the  bridge  to  the  middle  point  of  the  wire  and 
strike  again.     Is  the  pitch  higher  or  lower?     Does  a  short 
string  vibrate  faster  or  slower  than  a  long  one?     What  effect 
has  rate  of  vibration  on  the  pitch  of  a  sound? 

C.  Strike  the  wire  gently.     Note  the  distance  at  which 
the  sound  can  be  heard.     Strike  harder.     Is  the  tone  louder 


112  EXPEKIMENTAL   PHYSIOLOGY 

or  softer?  Can  it  be  heard  at  a  farther  distance?  Does  it 
vary  in  pitch?  What  effect  on  sound  does  extent  (ampli- 
tude) of  vibration  have? 

D.  Stand  at  the  point  where  you  can  just  hear  the  tick- 
ing of  a  watch.     Now  make  a  conical  tube  of  paper  and 
insert  the  small  end  in  the  ear.     Point  the  larger  end  toward 
the  watch.     Can  you  hear  it  any  better  now?     What  part 
of  the  ear  serves  a  purpose  similar  to  that  of  the  tube? 

E.  Sympathetic  Vibrations.     Tune  two  wires  to  the  same 
pitch.     Place  a  paper  rider  on  one  and  strike  the  other. 
What  happens  to  the  rider?     Lower  the  pitch  of  one  wire  and 
repeat.     Is  the  result  the  same? 

LXXV. — VISION;  DISSECTION  OF  SHEEP'S  EYE 

Apparatus.  —  Sheep's  skull  with  eyes  in  socket  (the  skull  used 
in  Ex.  LXVIII  will  serve  for  this  purpose),  scalpel,  scissors,  bone 
forceps,  evaporating  dish. 

Directions.  —  Cut  away,  with  the  bone  forceps,  the  bones 
that  inclose  the  eye,  so  that  it  may  be  seen  in  position  from 
the  side. 

A.  Muscles.  Notice  that  the  motion  of  the  eyeball  is 
controlled  by  six  muscular  bands.  Locate  the  attachment 
of  four  of  these  bands  on  the  top  (superior  rectus),  bottom 
(inferior  rectus),  side  near  nose  (internal  rectus),  and  side 
farthest  from  nose  (external  rectus).  Note  that  these  ex- 
tend directly  backward  to  the  end  of  the  socket  and  have 
their  origin  there.  What  motions  do  these  muscles  give  to 
the  eyeball?  Now  locate  on  the  top  of  the  eyeball  the  at- 
tachment of  a  transverse  band  of  muscle  (the  superior 
oblique)  and  follow  its  course,  through  a  tendon  pulley,  to 
its  origin  at  the  back  of  the  socket.  In  what  direction 
does  its  contraction  take  place?  What  motion  does  it  give 


SPECIAL   SENSES  113 

to  the  eye?  On  the  under  side  of  the  eye  locate  another 
transverse  muscle  (the  inferior  oblique).  Where  is  its  ori- 
gin? Has  it  a  pulley? 

B.  The  Externals  of  the  Eye.     Cut  the  muscle  bands  and 
trim  away  a  white  membrane  (the  conjunctiva,  a  continua- 
tion of  the  lining  of  the  eyelid)  in  the  front  of  the  eye.     Note 
that  the  eye  is  still  attached  to  the  socket  by  a  cord,  just 
below  and  outside  the  center  of  its  rear  surface.     This  is  the 
optic  nerve,  which  enters  the  eye  here  from  the  brain.     Pull 
the  eye  out  of  the  socket  and  cut  this  cord.     Now  examine 
the  outside  of  the  eyeball.     Note  that  it  is  covered  with  a 
firm  white  coat  (the  sclerotic)  except  in  the  front,  where  there 
is  a  clear  layer,  the  cornea,  usually  dulled  in  death. 

C.  The  Internals  of  the  Eye.     Hold  the  eye  with  the  cornea 
uppermost,  and  remove  this  with  the  scalpel  by  cutting  hori- 
zontally around  its  edge.     The  liquid  back  of  this  layer  is 
the  aqueous  humor.     Directly  back  of  the  cornea  appears  a 
circular  muscular  curtain — colored  in  the  human  eye  — 
called  the  iris,  and  in  its  center  a  hole  —  the  pupil.     What 
conclusions  do  you  draw  as  to  the  functions  of  this  iris  from 
comparing  the  size  of  the  pupil  of  your  own  eye,  when  look- 
ing at  a  bright  light,  with  its  size  when  in  a  dimly  lighted 
room?     Is  its  action  voluntary? 

Now  lay  the  eye  upon  its  side  in  the  evaporating  dish 
and  cover  it  with  water.  With  the  scalpel  cut  a  section 
through  the  entire  eye,  splitting  the  optic  nerve  (see  Fig. 
52).  Observe  the  following  parts:  just  back  of  the  iris 
the  convex  crystalline  lens  and  its  capsule;  the  muscles  that 
control  the  shape  of  the  lens  —  the  ciliary  muscles  —  and 
their  ligamentous  attachment  (suspensory  ligament);  on  the 
inside  of  the  layers  that  form  the  walls  of  the  eye,  at  the  edge 
of  the  lens,  a  black,  ridged  membrane  (the  ciliary  process)' 


114  EXPERIMENTAL   PHYSIOLOGY 

the  jellylike  mass  that  fills  the  body  of  the  eye  (vitreous 
humor) ;  the  three  layers  of  the  wall  of  the  eyeball,  —  outer 
(sclerotic),  middle  (choroid),  inner  (retina). 

Note  that  the  optic  nerve  pierces  the  two  outer  coats 
and  spreads  out  to  form  the  retina.  Remove  the  vitreous 
humor  and  notice  the  soft,  whitish  retina.  Tear  this  out 


CP 


FIQ.  52. —  Cross  Section  of  the  Eye:  Con,  conjunctiva;  Sc,  sclerotic;  C,  cornea;  A, 
aqueous  humor;  7,  iris;  L,  crystalline  lens;  Cm,  ciliary  muscles  and  ligament;  CP, 
ciliary  process;  V,  vitreous  humor;  Ch,  choroid;  R,  retina;  O,  optic  nerve. 

with  the  forceps  and  note  its  consistency  and  thickness. 
Under  this  observe  the  color  and  luster  of  the  choroid  coat. 
When  this  is  torn  out,  the  interlacing  blood  vessels  are  seen 
passing  from  one  layer  to  the  other. 

LXXVI.  —  ACTION  OF  THE  EYE 

Apparatus.  —  Model  of  eye. 

Directions.  —  Construct  a  model  of  the  eye  as  follows: 
Obtain  a  wooden  box  eighteen  or  twenty  inches  long  and 


SPECIAL   SENSES 


115 


about  eight  inches  wide  and  deep.  Leaving  one  side  open, 
paint  the  inside  of  the  box  black.  Around  the  open  side 
tack  a  piece  of  black  cloth  large  enough  to  cover  the  head 
of  the  observer  and  shut  out  the  light  from  the  interior  of 
the  box.  At  one  end  of  the  box  cut  a  hole  one  inch  in  di- 
ameter. Cut  several  black  cardboard  disks  to  fit  this  aper- 
ture, and  perforate  the  center  of  each  with  holes  varying 
from  one-sixteenth  to  one-half  inch  in  diameter.  Mount  a 
convex  lens  in  a  movable  holder  which  can  be  moved  for- 
ward and  backward  on  the  floor  of  the  box,  and  which  will 
bring  the  center  of  the  lens  opposite  the  center  of  the  hole. 


Diap) 

ragm  (Iris)                                        Screw 

i  (Retina)                         $ 

Lens 

A 
I 

/ 

*! 

\ 
t 

1 

| 

i 

1 

^ 

, 

1  gggg^JA 

w>^^m  \ 

FIG.  53. 

Mount  a  piece  of  ground  glass  in  the  same  way  to  serve  as  a 
screen.  Arrange  all  parts  as  in  Fig.  53. 

The  cardboard  disks  will  then  correspond  to  the  iris  with 
its  pupil;  the  walls  of  the  box  to  the  sclerotic;  the  black 
paint  to  the  choroid  (what  is  its  function?);  the  lens  to  the 
crystalline  lens,  and  the  screen  to  the  retina.  A  watch  glass 
placed  on  the  aperture  would  resemble  the  cornea. 

A.  Action  of  Parts.  Darken  the  room  and  place  a  lighted 
candle  at  a  distance  of  three  feet  from  the  aperture.  Place 
in  the  aperture  the  disk  with  one-quarter  inch  perforation. 
Cover  head  with  cloth  and  place  screen  at  the  rear  of  the 
box.  Now  move  the  lens  back  and  forth  until  there  ap- 


116  EXPERIMENTAL   PHYSIOLOGY 

pears  on  the  screen  a  sharp  image  of  the  candle  flame.  Is 
it  right  side  up?  What  is  the  function  of  the  lens?  Mark 
position  of  lens  and  screen.  Move  the  candle  three  feet 
farther  away.  Does  the  image  remain  on  the  screen?  Keep- 
ing the  lens  fixed,  move  the  screen  forward  in  the  box  until 
the  distinct  image  appears  again.  Return  the  screen  to  its 
original  position  and,  by  moving  the  lens,  cause  the  same 
result  —  an  image  on  the  screen.  Which  is  adjustable  in 
the  eye  —  the  screen  (retina)  or  lens?  How  is  the  lens  ad- 
justed in  the  eye?  (This  adjustment  of  the  lens  to  the  dis- 
tance of  objects  is  called  accommodation.)  Change  the  disks 
in  the  aperture,  using  first  larger  and  then  smaller  openings. 
Which  gives  the  brightest  image?  What  is  the  function  of 
the  iris? 

NOTE.  —  By  using  external  lenses  as  "  spectacles,"  shortsightedness 
and  longsightedness  can  be  correcte'd  and  illustrated. 


COLUfit 
PHARMACY 


BACTERIA 


&Y** 


LXXVII.  —  STUDY  OF  BACTERIA 

Apparatus. —  Culture  medium  (agar,  5  g.;1  Liebig  beef  extract, 
5  g.;  Peptone,  5  g.;  salt,  5  g.;  water,  500  c.c.),2  sterilized  Petri  dishes 
and  test  tubes,  compound  microscope,  microscope  slides,  cover  glasses, 
prepared  slides  of  coccus,  bacillus,  spirillum,  etc.,  forms,  needle  points, 
gentian  violet  stain,  litmus  paper. 

Directions.  —  A .  To  Demonstrate  the  Presence  of  Bacteria 
in  Air.  Take  two  Petri  dishes  containing  cooled  culture 
medium.  Examine,  and  note  the  transparent  character  of 
the  medium.  Now  remove  the  cover  of  one  of  the  dishes 
and  allow  it  to  remain  exposed  to  the  air  of  the  room  for  .ten 
minutes.  At  the  end  of  that  time  recover  it  and  set  aside 
in  a  temperature  of  36°  C.  Keep  the  cover  on  the  second 
dish  (control)  and  set  it  aside  with  the  first  dish.  (N.B. 
Other  dishes  prepared  in  the  same  way  may  be  exposed  in 
various  places  to  give  variety  and  comparative  results.) 
Examine  these  dishes  from  day  to  day  until  spots  appear  on 
their  surface.  Describe  the  color  and  appearance  of  these 

*  Agar  makes  a  firmer  jelly  and  is  better  for  general  use.  In  case  it 
is  not  available  gelatin  may  be  used.  In  that  case  take  50  g.  of  gelatin. 

2  First  dissolve  in  water  all  the  ingredients  except  the  agar  and  neu- 
tralize with  sodium  carbonate  if  necessary.  Next  dissolve  the  agar  in 
boiling  water  and  add,  with  stirring,  the  first  solution.  Neutralize 
again  with  sodium  carbonate  if  necessary.  Make  up  to  500  c.c.  with 
water,  boil  and  filter  hot  through  absorbent  cotton.  Pour  this  hot 
liquid  into  sterilized  Petri  dishes  and  test  tubes  as  desired.  Cover  the 
dishes  and  plug  the  ends  of  the  test  tubes  with  sterilized  absorbent  cotton. 

117 


118  EXPERIMENTAL   PHYSIOLOGY 

spots.  Then  with  the  needle  point  remove  some  of  the 
spots  to  a  slide,  cover  with  a  glass,  run  a  little  water  under 
the  glass,  and  examine  under  the  high  power  of  the  com- 
pound microscope.  Describe  with  drawings  what  you  see. 
Smear  a  little  of  one  of  the  spots  on  a  cover  glass  and  pass 
the  glass  through  a  gas  flame  two  or  three  times  until  dry. 
Mount  the  glass,  smear  side  down,  on  a  microscope  slide. 
Run  a  little  gentian  violet  under  the  cover  glass  and  after  a 
few  minutes  examine  again.  What  effect  has  the  stain? l 

Do  spots  appear  on  the  control  dish?  What  does  this 
prove  as  to  the  origin  of  the  bacteria?  Are  the  bacteria  all 
alike  in  size  and  shape?  Do  all  or  any  of  them  move?  Are 
the  spots  all  alike  in  color  and  shape?  Examine  several  as 
above  and  report  your  results  with  drawings  of  the  forms 
observed. 

Write  a  detailed  statement  telling  what  you  have  learned 
about  bacteria  from  this  experiment. 

B.  To   Demonstrate  the   Presence   of  Bacteria  in  Water. 
Take  two  test  tubes  containing  culture  medium.     Pour  into 
one  10  c.c.  of  ordinary  drinking  water  and  plug  with  ster- 
ilized cotton.     Boil  some  water  and  pour  10  c.c.  into  the 
second  tube.     Plug  in  same  way  as  first.     Place  both  tubes 
at  36°  C.  and  let  stand  several  days.    At  the  end  of  that  time 
examine  both  tubes.     Describe  the  difference  in  appearance, 
odor,  reaction  to  litmus.     Examine  a  drop  of  the  water  from 
each  on  a  microscope  slide.  Record  the  results  with  drawings. 
Why  does  boiling  water  prevent  infection? 

C.  To  Demonstrate  the  Forms  of  Bacteria.     Examine  pre- 
pared slides  of  various  types  of  bacteria  and  make  drawings 
of  same. 

D.  Variations  of  the  Above  Experiments. 

1  Bacteria  do  not  stain  readily  until  killed  by  heat  or  other  means. 


BACTERIA  119 

(a)  Conditions  favorable  and  unfavorable  to  growth  may 
be  determined  by  modifications  of  B. 

(6)  Protection  from  dust  may  be  shown  as  a  modification 
of  A. 

(c)  Other  substances  may  be  substituted  for  water  in  B. 

(d)  The  preparation  of  pure  cultures  may  be  shown  by 
transferring  to  new  dishes  the  colonies  obtained  in  A. 

(e)  Examination  for  disease  germs  may  be  demonstrated 
by  transferring  mucus  from  throat,  dirt  from  finger  nails, 
blood,  etc.,  to  prepared  dishes  and  examining  the  results  as 
described  in  A  and  B. 


PAYNE'S   MANUAL   OF 
EXPERIMENTAL   BOTANY 

By  FRANK  OWEN  PAYNE,  M.Sc.,  Assistant    in  Bio- 
logy, High  School  of  Commerce,  New  York 

75  cents 

THIS  laboratory  manual  presents  a  complete  elementary 
course  for  high  schools,  in  which  botany  is  continuously 
correlated  with  practical  gardening,   farming,  and  bac- 
teriology.    It  may  be  used  independently  or  to  supplement 
any  textbook. 

^[  The  controlling  idea  has  been  to  provide  applications  of 
vital  principles  which  will  be  of  real  practical  value  to  pupils 
in  their  daily  living  and  will  help  to  make  them  better  and 
more  intelligent  citizens. 

^[  Outlines  are  given  for  228  experiments,  dealing  with  the 
following  topics:  common  elements,  food  materials,  osmosis, 
soils,  seed  plants — from  seed  to  fruit,  and  cryptogams.  Each 
outline  consists  of  a  statement  of  the  object  of  the  experiment, 
a  list  of  apparatus,  directions  for  doing  the  work,  and  ques- 
tions or  suggestions  to  guide  the  pupil  to  the  interpretation  of 
the  results. 

^[  The  wealth  of  material  includes  so  many  alternative  ex- 
periments that  teachers  will  be  enabled  to  adapt  their  work  to 
their  special  conditions  and  to  follow  a  choice  of  topics  from 
year  to  year.  Besides  the  exercises  to  be  performed  in  the 
classroom,  others  are  provided  for  home  work. 
^[  The  drills  are  chiefly  in  function,  requiring  little  dissec- 
tion and  only  simple  lenses.  The  laboratory  equipment 
needed  is  simple,  and  much  of  it  can  be  made  at  home  at 
small  expense. 

^|  The  course  includes  all  the  experiments  usually  demanded 
for  entrance  to  college,  and  meets  the  requirements  of  the 
New  York  State  Academic  Syllabus. 

AMERICAN    BOOK    COMPANY 

(166) 


PLANT      LIFE      AND 
PLANT      USES 

By  JOHN  GAYLORD  COULTER,  Ph.  D. 

$1.20 


AN  elementary  textbook  providing  a  foundation  for  the 
study  of  agriculture,  domestic  science,  or  college  botany. 
But  it  is  more  than  a  textbook  on  botany — it  is  a  book 
about  the  fundamentals  of  plant  life  and  about  the  relations 
between  plants  and  man.  It  presents  as  fully  as  is  desirable 
for  required  courses  in  high  schools  those  large  facts  about 
plants  which  form  the  present  basis  of  the  science  of  botany. 
Yet  the  treatment  has  in  view  preparation  for  life  in  general, 
and  not  preparation  for  any  particular  kind  of  calling. 

The  subject  is  dealt  with  from  the  viewpoint  of  the  pupil 
rather  than  from  that  of  the  teacher  or  the  scientist.  The 
style  is  simple,  clear,  and  conversational,  yet  the  method  is 
distinctly  scientific,  and  the  book  has  a  cultural  as  well  as 
a  practical  object. 

The  text  has  a  unity  of  organization.  So  far  as  practicable 
the  familiar  always  precedes  the  unfamiliar  in  the  sequence  of 
topics,  and  the  facts  are  made  to  hang  together  in  order  that 
the  pupil  may. see  relationships.  Such  topics  as  forestry,  plant 
breeding,  weeds,  plant  enemies  and  diseases,  plant  culture, 
decorative  plants,  and  economic  bacteria  are  discussed  where 
most  pertinent  to  the  general  theme  rather  than  in  separate 
chapters  which  destroy  the  continuity.  Trie  questions  and 
suggestions  which  follow  the  chapters  are  of  two  kinds ;  some 
are  designed  merely  to  serve  as  an  aid  in  the  study  of  the  text, 
while  others  suggest  outside  study  and  inquiry.  The  classified 
tables  of  terms  which  precede  the  index  are  intended  to  serve 
the  student  in  review,  and  to  be  a  general  guide  to  the  relative 
values  of  the  facts  presented.  More  than  200  attractive  illus- 
trations, many  of  them  original,  are  included  in  the  book. 


AMERICAN     BOOK     COMPANY 

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CLARK'S 
GENERAL       SCIENCE 

By  BERTHA  M.  CLARK,  Ph.D.,  Head  of  Science 
Department,  William  Penn  High  School  for  Girls,  Phila- 
delphia, Pa. 

$0.80 

Laboratory  Manual,  to  accompany  the  textbook 
$0.40 


THIS  course  in  general  science,  which  was  successfully 
developed  by  the  author  for  use  in  her  classes,  is  suit- 
able for  pupils  in  the  high  school  course  who  do  not 
go  to  college.  While  it  deals  with  physics,  chemistry  and 
hygiene,  the  controlling  idea  has  been  to  make  the  presenta- 
tion as  informal  and  untechnical  as  possible,  to  arouse  the  in- 
terest of  the  student,  and  to  provide  information  which  will 
broaden  his  horizon  and  be  of  real  practical  value.  Each  topic 
describes  some  interesting  phenomenon  commonly  met  in  every- 
day life,  and  afterwards  discusses  in  a  popular  style  the  scientific 
principles  on  which  it  is  based.  The  meeting  wisely  of  some 
of  life's  important  problems,  the  conservation  of  energy,  and 
the  comprehension  of  many  important  inventions  receive  atten- 
tion, yet  throughout  due  regard  is  paid  to  mental  training. 
^[  Practical  laboratory  work  in  connection  with  the  study  of 
this  book  is  provided  in  the  Laboratory  Manual,  in  which 
eighty-nine  experiments  are  presented,  which  are  designed  to 
make  the  pupil  familiar  with  some  of  the  facts  and  theories 
discussed  in  the  author's  textbook  on  general  science.  The 
experiments,  which  are  accompanied  by  full  directions,  can 
easily  be  performed  with  simple  apparatus.  Among  the  sub- 
jects treated  are  temperature,  ventilation,  composition  and  purity 
of  foods,  purification  of  water,  lenses  and  photographic  paper, 
tests  for  eyesight  and  hearing,  some  principles  of  machines, 
soap  making,  baking  soda,  bleaching  powders,  dyeing,  artifi- 
cial coloring  and  preservatives  in  foods,  sound,  electricity,  etc. 


AMERICAN    BOOK    COMPANY 


ESSENTIALS    OF    PHYSICS 

By  GEORGE  A.   HOADLEY,   C.E.,  Sc.  D.,  Professor 
of  Physics,  Swarthmore  College. 

$1.25 


THIS  is  the  author's  popular  and  successful  Elements  of 
Physics  enriched  and  brought  up  to  date.     Despite  the 
many  changes  and   modifications   made   in   this   new 
edition,  it  retains  the  qualities  which  have  secured  so  great  a 
success  for  the  previous  book. 

^[  It  tells  only  what  everyone  should  know,  and  it  does  this 
in  a  straightforward,  concise,  and  interesting  manner.  It  takes 
into  consideration  the  character  of  high  school  needs  and  con- 
ditions, and,  throughout,  lays  particular  emphasis  upon  the 
intimate  relation  between  physics  and  everyday  life. 
^j  While  the  subject  matter,  as  a  whole,  is  unchanged,  the 
order  of  topics  in  many  cases  has  been  altered  to  adapt  the 
development  of  the  subject  to  the  habits  of  thought  of  high 
school  pupils.  Instead  of  beginning  the  treatment  of  a  sub- 
ject with  the  definition  and  proceeding  to  a  discussion  of  the 
sub-topics,  the  author  starts  with  a  discussion  of  well-known 
phenomena  and  leads  up  to  the  definition  of  the  subject  dis- 
cussed. The  text,  wherever  possible,  has  been  simplified, 
more  than  fifty  topics  having  been  amplified,  expanded,  or 
reworded.  More  familiar  illustrations  of  the  topics  treated 
are  given,  and  the  demonstrations  of  many  of  the  experiments 
are  simplified  by  the  use  of  materials  that  are  readily  obtain- 
able in  the  classroom. 

^[  There  have  been  added  a  number  of  new  topics,  mostly 
in  connection  with  the  recent  advances  in  applied  science. 
The  number  both  of  questions  and  problems  has  been  greatly 
increased  and  the  data  in  these  all  relate  to  actual,  practical, 
physical  phenomena.  More  than  one-fifth  of  the  illustrations 
in  the  book  are  new,  many  of  the  pictures  of  apparatus  having 
been  redrawn  to  show  modern  forms. 


AMERICAN    BOOK    COMPANY 

(-56) 


A    NEW  ASTRONOMY 


By  DAVID  TODD,  M.A.,  Ph.D.,  Professor  of  Astron- 
omy and  Navigation,  and  Director  of  the  Observatory, 
Amherst  College. 


A  STRONG  MY  is  here  presented  as  preeminently  a 
jfX,  science  of  observation.  More  of  thinking  than  of 
memorizing  is  required  in  its  study,  and  greater  emphasis 
is  laid  on  the  physical  than  on  the  mathematical  aspects  of 
the  science.  As  in  physics  and  chemistry  the  fundamental 
principles  are  connected  with  tangible,  familiar  objects,  and 
the  student  is  shown  how  he  can  readily  make  apparatus  to 
illustrate  them. 

^[  In  order  to  secure  the  fullest  educational  value  astronomy 
is  regarded,  not  as  a  mere  sequence  of  isolated  and  imperfectly 
connected  facts,  but  as  an  inter-related  series  of  philosophic 
principles.  The  geometrical  concept  of  the  celestial  sphere  is 
strongly  emphasized;  also  its  relation  to  astronomical  instru- 
ments. But  even  more  important  than  geometry  is  the  philo- 
sophical correlation  of  geometric  systems.  Ocean  voyages 
being  no  longer  uncommon,  the  author  has  given  rudimemtal 
principles  of  navigation  in  which  astronomy  is  concerned. 
^[  The  treatment  of  the  planets  is  not  sub-divided  according 
to  the  planets  themselves,  as  is  usual,  but  according  to  special 
elements  and  features.  The  law  of  universal  gravitation  is 
unusually  full,  clear,  and  illuminating.  The  marvelous  dis- 
coveries in  recent  years  and  the  advance  in  methods  of  teach- 
ing are  properly  recognized,  while  such  interesting  subjects 
as  the  astronomy  of  navigation,  the  observatory  and  its 
instruments,  and  the  stars  and  the  cosmogony  receive  particu- 
lar attention. 

^[  The  illustrations  demand  special  mention;  many  of  them 
are  so  ingeniously  devised  that  they  explain  at  a  glance  what 
many  pages  of  description  could  not  make  clear. 


AMERICAN     BOOK     COMPANY 

(181) 


ELEMENTS    OF   GEOLOGY 

By  ELIOT  BLACKWELDER,  Associate  Professor  of 
Geology,  University  of  Wisconsin,  and  HARLAN  H. 
BARROWS,  Associate  Professor  of  General  Geology 
and  Geography,  University  of  Chicago. 


AN  introductory  course  in  geology,  complete  enough  for 
college  classes,  yet  simple  enough  for  high  school  pu- 
pils.     The  text  is  explanatory,    seldom  merely  des- 
criptive, and  the  student  gains  a  knowledge  not  only  of  the 
salient  facts  in  the  history  of  the  earth,  but  also  of  the  methods 
by  which  those  facts  have  been  determined.      The  style  is 
simple  and  direct.     Few  technical  terms  are  used.     The  book 
is  exceedingly  teachable. 

^|  The  volume  is  divided  into  two  parts,  physical  geology 
and  historical  geology.  It  differs  more  or  less  from  its  prede- 
cessors in  the  emphasis  on  different  topics  and  in  the  arrange- 
ment of  its  material.  Factors  of  minor  importance  in  the  de- 
velopment of  the  earth,  such  as  earthquakes,  volcanoes,  and 
geysers,  are  treated  much  more  briefly  than  is  customary. 
This  has  given  space  for  the  extended  discussion  of  matters 
of  greater  significance.  For  the  first  time  an  adequate  discus- 
sion of  the  leading  modern  conceptions  concerning  the  origin 
and  early  development  of  the  earth  is  presented  in  an  ele- 
mentary textbook. 

^J  The  illustrations  and  maps,  which  are  unusually  numerous, 
really  illustrate  the  text  and  are  referred  to  definitely  in  the 
discussion.  They  are  admirably  adapted  to  serve  as  the  basis 
for  classroom  discussion  and  quizzes,  and  as  such  constitute  one 
of  the  most  important  features  of  the  book.  The  questions  at 
the  end  of  the  chapters  are  distinctive  in  that  the  answers  are 
in  general  not  to  be  found  in  the  text.  They  may,  how- 
ever, be  reasoned  out  by  the  student,  provided  he  has  read 
the  text  with  understanding. 


AMERICAN     BOOK     COMPANY 


MAYNE   &   HATCH'S    HIGH 
SCHOOL    AGRICULTURE 

By  D.  D.  MAYNE,  Principal  of  School  of  Agriculture  and 
Professor  of  Agricultural  Pedagogics,  University  of  Min- 
nesota; and  K.  L.  HATCH,  Professor  of  Agricul- 
tural Education,  University  of  Wisconsin. 

$1.00 


THIS  course  has  a  double  value  for  pupils  in  the  first 
years  of  the  high  school.  Oji  the  one  hand,  it  puts 
the  study  of  agriculture  on  a  serious  basis  and  teaches 
the  young  beginner  how  he  can  carry  on  the  work  of  a  farm 
most  profitably.  On  the  other  hand,  it  affords  an  interesting 
introduction  to  all  the  natural  sciences,  enabling  the  student  to 
master  certain  definite  principles  of  chemistry,  botany,  and 
zoology,  and  to  understand  their  applications.  A  few  experi- 
ments are  included,  which  may  be  performed  by  the  student 
or  by  the  teacher  before  the  class.  But  the  subject  is  not 
made  ultrascientific,  forcing  the  student  through  the  long 
process  of  laboratory  method  to  rediscover  what  scientists 
have  fully  established. 

^j  The  topics  are  taken  up  in  the  text  in  their  logical  order. 
The  treatment  begins  with  an  elementary  agricultural  chem- 
istry, in  which  are  discussed  the  elements  that  are  of  chief 
importance  in  plant  and  animal  life.  Following  in  turn  are 
sections  on  soils  and  fertilizers ;  agricultural  botany ;  economic 
plants,  including  field  and  forage  crops,  fruits  and  vege- 
tables; plant  diseases;  insect  enemies;  animal  husbandry;  and 
farm  management. 

^|  The  chapter  on  plant  diseases,  by  Dr.  E.  M.  Freeman, 
Professor  of  Botany  and  Vegetable  Pathology,  College  of 
Agriculture,  University  of  Minnesota,  describes  the  various 
fungus  growths  that  injure  crops,  and  suggests  methods  of 
fighting  them.  The  section  on  farm  management  treats  farm- 
ing from  the  modern  standpoint  as  a  business  proposition. 


AMERICAN    BOOK    COMPANY 

(324; 


DESCRIPTIVE 

CATALOGUE  OF  HIGH 

SCHOOL  AND  COLLEGE 

TEXTBOOKS 

Published  Complete  and  in   Sections 


WE  issue  a  Catalogue  of  High  School  and  College  Text- 
books, which  we  have  tried  to  make  as  valuable  and 
as  useful  to  teachers  as  possible.       In  this    catalogue 
are  set  forth  briefly  and  clearly  the  scope  and  leading  charac- 
teristics of  each  of  our  best  textbooks.      In  most  cases  there 
are  also  given  testimonials  from  well-known  teachers,  which 
have  been  selected  quite  as  much  for  their  descriptive  qualities 
as  for  their  value  as  commendations. 

^j  For  the  convenience  of  teachers  this  Catalogue  is  also 
published  in  separate  sections  treating  of  the  various 
branches  of  study.  These  pamphlets  are  entitled :  Eng- 
lish, Mathematics,  History  and  Political  Science,  Science, 
Modern  Foreign  Languages,  Ancient  Languages,  Com- 
mercial Subjects,  and  Philosophy  and  Education.  A 
single  pamphlet  is  devoted  to  the  Newest  Books  in  all 
subjects. 

*J|  Teachers  seeking  the  newest  and  best  books  for  their 
classes  are  invited  to  send  for  our  Complete  High  School  and 
College  Catalogue,  or  for  such  sections  as  may  be  of  greatest 
interest. 

^[  Copies  of  our  price  lists,  or  of  special  circulars,  in  which 
these  books  are  described  at  greater  length  than  the  space 
limitations  of  the  catalogue  permit,  will  be  mailed  to  any 
address  on  request. 

^|  All  correspondence  should  be  addressed  to  the  nearest 
of  the  following  offices  of  the  company:  New  York,  Cincin- 
nati, Chicago,  Boston,  Atlanta,  San  Francisco. 


AMERICAN     BOOK     COMPANY 

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